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  • oxidation  (328)
  • Springer  (328)
  • American Meteorological Society
  • 1995-1999  (216)
  • 1980-1984  (55)
  • 1975-1979  (57)
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  • 1
    Electronic Resource
    Electronic Resource
    Purification and characterization of fumarase from the syntrophic propionate-oxidizing bacterium strain MPOB (1996)
    Springer
    Archives of microbiology 165 (1996), S. 126-131 
    Details
    ISSN: 1432-072X
    Keywords: Key words Fumarase ; Syntrophy ; Propionate ; oxidation ; Fumarate fermentation ; Anaerobic oxidation ; Iron-sulfur cluster
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Fumarase from the syntrophic propionate-oxidizing bacterium strain MPOB was purified 130-fold under anoxic conditions. The native enzyme had an apparent molecular mass of 114 kDa and was composed of two subunits of 60 kDa. The enzyme exhibited maximum activity at pH 8.5 and approximately 54° C. The K m values for fumarate and l-malate were 0.25 mM and 2.38 mM, respectively. Fumarase was inactivated by oxygen, but the activity could be restored by addition of Fe2+ and β-mercaptoethanol under anoxic conditions. EPR spectroscopy of the purified enzyme revealed the presence of a [3Fe-4S] cluster. Under reducing conditions, only a trace amount of a [4Fe-4S] cluster was detected. Addition of fumarate resulted in a significant increase of this [4Fe-4S] signal. The N-terminal amino acid sequence showed similarity to the sequences of fumarase A and B of Escherichia coli (56%) and fumarase A of Salmonella typhimurium (63%).
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s002030050307
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  • 2
    Electronic Resource
    Electronic Resource
    Investigation of the fumarate metabolism of the syntrophic propionate-oxidizing bacterium strain MPOB (1998)
    Springer
    Archives of microbiology 169 (1998), S. 346-352 
    Details
    ISSN: 1432-072X
    Keywords: Key words Syntrophy ; Fumarate reduction ; Propionate ; oxidation ; Anaerobic growth ; Electron transport chain
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The growth of the syntrophic propionate-oxidizing bacterium strain MPOB in pure culture by fumarate disproportionation into carbon dioxide and succinate and by fumarate reduction with propionate, formate or hydrogen as electron donor was studied. The highest growth yield, 12.2 g dry cells/mol fumarate, was observed for growth by fumarate disproportionation. In the presence of hydrogen, formate or propionate, the growth yield was more than twice as low: 4.8, 4.6, and 5.2 g dry cells/mol fumarate, respectively. The location of enzymes that are involved in the electron transport chain during fumarate reduction in strain MPOB was analyzed. Fumarate reductase, succinate dehydrogenase, and ATPase were membrane-bound, while formate dehydrogenase and hydrogenase were loosely attached to the periplasmic side of the membrane. The cells contained cytochrome c, cytochrome b, menaquinone-6 and menaquinone-7 as possible electron carriers. Fumarate reduction with hydrogen in membranes of strain MPOB was inhibited by 2-(heptyl)-4-hydroxyquinoline-N-oxide (HOQNO). This inhibition, together with the activity of fumarate reductase with reduced 2,3-dimethyl-1,4-naphtoquinone (DMNH2) and the observation that cytochrome b of strain MPOB was oxidized by fumarate, suggested that menequinone and cytochrome b are involved in the electron transport during fumarate reduction in strain MPOB. The growth yields of fumarate reduction with hydrogen or formate as electron donor were similar to the growth yield of Wolinella succinogenes. Therefore, it can be assumed that strain MPOB gains the same amount of ATP from fumarate reduction as W. succinogenes, i.e. 0.7 mol ATP/mol fumarate. This value supports the hypothesis that syntrophic propionate-oxidizing bacteria have to invest two-thirds of an ATP via reversed electron transport in the succinate oxidation step during the oxidation of propionate. The same electron transport chain that is involved in fumarate reduction may operate in the reversed direction to drive the energetically unfavourable oxidation of succinate during syntrophic propionate oxidation since (1) cytochrome b was reduced by succinate and (2) succinate oxidation was similarly inhibited by HOQNO as fumarate reduction.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s002030050581
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  • 3
    Electronic Resource
    Electronic Resource
    Heterologous expression of soluble methane monooxygenase genes in methanotrophs containing only particulate methane monooxygenase (1999)
    Springer
    Archives of microbiology 171 (1999), S. 364-370 
    Details
    ISSN: 1432-072X
    Keywords: Key words Heterologous expression ; Methane ; oxidation ; Methane monooxygenase ; Methanotroph ; Regulation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The methanotrophs Methylococcus capsulatus (Bath) and Methylosinus trichosporium OB3b contain particulate methane monooxygenase (pMMO) and soluble methane monooxygenase (sMMO) genes. Other methanotrophs such as Methylomicrobium album BG8 and Methylocystis parvus OBBP contain only pMMO genes. Although molecular genetic techniques are poorly developed in methanotrophs, sMMO genes were expressed in methanotrophs normally containing only pMMO genes. This was achieved by conjugation using broad-host-range plasmids containing the native promoter and sMMO genes from Mc. capsulatus (Bath) and Ms. trichosporium OB3b. sMMO genes derived from Ms. trichosporium OB3b were expressed in an active form in Mcy. parvus OBBP and in Mm. album BG8. Therefore, all of the genes required for active sMMO synthesis were contained on the broad-host-range plasmids and were expressed in the heterologous hosts. Constitutive synthesis of pMMO was observed in Mm. album BG8 when grown at high and low copper-to-biomass ratios, while transcription of the recombinant sMMO genes was only observed under growth conditions of low copper-to-biomass ratios. Therefore, the regulatory protein(s) for sMMO synthesis was also present on the plasmid used, or the heterologous host contained a regulatory system for sMMO. Expression of sMMO genes in methanotrophs containing only pMMO will assist further investigations on the expression and regulation of MMO genes in methanotrophs.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s002030050723
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  • 4
    Electronic Resource
    Electronic Resource
    A new obligately chemolithoautotrophic, nitrite-oxidizing bacterium, Nitrospira moscoviensis sp. nov. and its phylogenetic relationship (1995)
    Springer
    Archives of microbiology 164 (1995), S. 16-23 
    Details
    ISSN: 1432-072X
    Keywords: Key wordsNitrospira moscoviensis ; Non-marine ; bacteria ; Obligate chemolithoautotroph ; Nitrite ; oxidation ; Nitrate reduction ; 16S rRNA gene sequences
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract A gram-negative, non-motile, non-marine, nitrite-oxidizing bacterium was isolated from an enrichment culture initiated with a sample from a partially corroded area of an iron pipe of a heating system in Moscow, Russia. The cells were 0.9–2.2 μm × 0.2–0.4 μm in size. They were helical- to vibroid-shaped and often formed spirals with up to three turns 0.8–1.0 μm in width. The organism possessed an enlarged periplasmic space and lacked intracytoplasmic membranes and carboxysomes. The cells tended to excrete extracellular polymers, forming aggregates. The bacterium grew optimally at 39°C and pH 7.6– 8.0 in a mineral medium with nitrite as sole energy source and carbon dioxide as sole carbon source. The optimal nitrite concentration was 0.35 mM. Nitrite was oxidized to nitrate stoichiometrically. The doubling time was 12 h in a mineral medium with 7.5 mM nitrite. The cell yield was low; only 0.9 mg protein/l was formed during oxidation of 7.5 mM nitrite. Under anoxic conditions, hydrogen was used as electron donor with nitrate as electron acceptor. Organic matter (yeast extract, meat extract, peptone) supported neither mixotrophic nor heterotrophic growth. At concentrations as low as 0.75 g organic matter/l or higher, growth of nitrite-oxidizing cells was inhibited. The cells contained cytochromes of the b- and c-type. The G+C content of DNA was 56.9 ± 0.4 mol%. The chemolithoautotrophic nitrite-oxidizer differed from the terrestrial members of the genus Nitrobacter with regard to morphology and substrate range and equaled Nitrospira marina in both characteristics. The isolated bacterium is designated as a new species of the genus Nitrospira. Comparative analysis of 16S rRNA gene sequences revealed a moderate phylogenetic relationship to Nitrospira marina, leptospirilla, Thermodesulfovibrio yellowstonii, "Magnetobacterium bavaricum," and the isolate OPI-2. Initial evidence is given that these organisms represent a new phylum of the domain bacteria.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s002030050230
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  • 5
    Electronic Resource
    Electronic Resource
    Anaerobic ammonia oxidation with nitrogen dioxide by Nitrosomonas eutropha (1997)
    Springer
    Archives of microbiology 167 (1997), S. 106-111 
    Details
    ISSN: 1432-072X
    Keywords: Key wordsNitrosomonas ; Anaerobic ammonia ; oxidation ; Anaerobic cell growth ; Nitrogen dioxide ; Nitric oxide ; Nitrous oxide ; Dinitrogen
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Nitrosomonas eutropha, an obligately lithoautotrophic bacterium, was able to nitrify and denitrify simultaneously under anoxic conditions when gaseous nitrogen dioxide (NO2) was supplemented to the atmosphere. In the presence of gaseous NO2, ammonia was oxidized, nitrite and nitric oxide (NO) were formed, and hydroxylamine occurred as an intermediate. Between 40 and 60% of the produced nitrite was denitrified to dinitrogen (N2). Nitrous oxide (N2O) was shown to be an intermediate of denitrification. Under an N2 atmosphere supplemented with 25 ppm NO2 and 300 ppm CO2, the amount of cell protein increased by 0.87 mg protein per mmol ammonia oxidized, and the cell number of N. eutropha increased by 5.8 × 109 cells per mmol ammonia oxidized. In addition, the ATP and NADH content increased by 4.3 μmol ATP (g protein)–1 and 6.3 μmol NADH (g protein)–1 and was about the same in both anaerobically and aerobically grown cells. Without NO2, the ATP content decreased by 0.7 μmol (g protein)–1, and the NADH content decreased by 1.2 μmol (g protein)–1. NO was shown to inhibit anaerobic ammonia oxidation.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s002030050422
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  • 6
    Electronic Resource
    Electronic Resource
    Sulfide-quinone reductase activity in membranes of the chemotrophic bacterium Paracoccus denitrificans GB17 (1998)
    Springer
    Archives of microbiology 170 (1998), S. 353-360 
    Details
    ISSN: 1432-072X
    Keywords: Key wordsParacoccus denitrificans ; Sulfide ; oxidation ; Sulfide-quinone reductase ; Cytochrome ; bc complex ; Flavocytochrome c
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Reduction of exogenous ubiquinone and of cytochromes by sulfide in membranes of the chemotrophic bacterium Paracoccus denitrificans GB17 was studied. For sulfide-ubiquinone reductase activity, K m values of 26 ± 4 and 3.1 ± 0.6 μM were determined from titrations with sulfide and decyl-ubiquinone, respectively. A maximal rate of up to 0.3 μmol decyl-ubiquinone reduced (mg protein)–1 min–1 was estimated. The reaction was sensitive to quinone-analogous inhibitors, but insensitive to cyanide. Reduction of cytochromes by sulfide was monitored with an LED-array spectrophotometer. Under oxic conditions, reduction rates and extents of reduction were lower than those under anoxic conditions. Reoxidation of cytochromes was oxygen-dependent and cyanide-sensitive. The multiphasic behavior of transient reduction of cytochrome b with limiting amounts of sulfide reflects that sulfide, in addition to acting as an electron donor, is a slowly binding inhibitor of cytochrome c oxidase. The initial peak of cytochrome b reduction is dependent on electron flow to an oxidant, either oxygen or ferricyanide, and is stimulated by antimycin A. This oxidant-induced reduction of cytochrome b suggests that electron transport from sulfide in P. denitrificans GB17 employs the cytochrome bc 1 complex via the quinone pool.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s002030050653
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  • 7
    Electronic Resource
    Electronic Resource
    Sulfur colloids as temporary energy reservoirs for Thiobacillus ferrooxidans during pyrite oxidation (1995)
    Springer
    Archives of microbiology 163 (1995), S. 352-356 
    Details
    ISSN: 1432-072X
    Keywords: Key wordsThiobacillus ferrooxidans ; Sulfide ; oxidation ; Sulfur colloids ; Bioleaching
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Thiobacillus ferrooxidans was cultivated on 100-nm-thick synthetic pyrite (FeS2) films. The steps of biooxidation were studied with high-resolution transmission electron microscopy. The crystallized sulfide was transformed into colloidal sulfur (4–70 nm, depending on the age of the cell and the degree of substrate oxidation; 70 nm initially and 4 nm after oxidation of the pyrite substrate), which was taken up and distributed over an organic capsule around the bacteria. This colloidal sulfur acted as intermediate energy storage and was transferred by contact to daughter cells not directly attached to the sulfide substrate.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00404208
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  • 8
    Electronic Resource
    Electronic Resource
    Metabolic oxidation of methaqualone in extensive and poor metabolisers of debrisoquine (1982)
    Springer
    European journal of clinical pharmacology 23 (1982), S. 147-150 
    Details
    ISSN: 1432-1041
    Keywords: methaqualone ; debrisoquine ; pharmacogenetics ; metabolism ; oxidation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary The metabolism of methaqualone to the glucuronides of 5 C-monohydroxy metabolites and to the N-oxide has been studied in 2 groups of healthy young adults phenotyped as extensive and poor metabolisers of debrisoquine. No significant interphenotype differences were observed with respect to the excretion of any of the 6 metabolites. It is probable that the genetic regulation of the pathways leading to these metabolites is at a locus other than that which is responsible for the regulation of the oxidation of debrisoquine, guanoxan, phenacetin, phenytoin and sparteine.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00545969
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  • 9
    Electronic Resource
    Electronic Resource
    Sol-Gel Coatings on Metals (1997)
    Springer
    Journal of sol gel science and technology 8 (1997), S. 443-449 
    Details
    ISSN: 1573-4846
    Keywords: coatings ; protection of metals ; oxidation ; corrosion
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract Sol-gel derived films can be deposited on metals to improve their resistance to oxidation and corrosion or to modify their surface properties. However, practical applications are limited by problems intrinsic to sol-gel processing or specific of coating/metal systems. Coatings aimed to improve oxidation and wet corrosion resistance have been the most studied. The results published in the literature show that sol-gel coatings may offer good protection against oxidation. More difficult is to achieve a protection against wet corrosion. An important aspect of the application of the sol-gel method for coating metallic objects is also the deposition technique.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1018373404815
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  • 10
    Electronic Resource
    Electronic Resource
    Sol-gel coatings on metals (1997)
    Springer
    Journal of sol gel science and technology 8 (1997), S. 443-449 
    Details
    ISSN: 1573-4846
    Keywords: coatings ; protection of metals ; oxidation ; corrosion
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract Sol-gel derived films can be deposited on metals to improve their resistance to oxidation and corrosion or to modify their surface properties. However, practical applications are limited by problems intrinsic to sol-gel processing or specific of coating/metal systems. Coatings aimed to improve oxidation and wet corrosion resistance have been the most studied. The results published in the literature show that sol-gel coatings may offer good protection against oxidation. More difficult is to achieve a protection against wet corrosion. An important aspect of the application of the sol-gel method for coating metallic objects is also the deposition technique.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02436880
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  • 11
    Electronic Resource
    Electronic Resource
    Work Function of PbZrO3 (1998)
    Springer
    Journal of materials synthesis and processing 6 (1998), S. 335-338 
    Details
    ISSN: 1573-4870
    Keywords: PbZrO3 ; oxidation ; nonstoichiometry
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract This paper reports the results of work function (WF) changes of undoped PbZrO3 during subsequent isothermal oxidation and reduction experiments at 500°C in the p(O2) range between 10 and 2.1 × 104 Pa. The results, obtained during three consecutive runs, indicate that heating at 500°C leads to continuous changes of surface properties resulting in a complex WF vs. time characteristic. The WF changes during the first oxidation are determined by a p(O2)-induced structural transition. The second oxidation results in two competitive processes, such as rapid increase of oxygen non-stoichiometry followed by a structural transition. Finally, the third oxidation is determined by changes of oxygen nonstoichiometry.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1022603327570
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  • 12
    Electronic Resource
    Electronic Resource
    Effect of Surface Preparation of Zirconia on its Reactivity with Oxygen (1998)
    Springer
    Journal of materials synthesis and processing 6 (1998), S. 373-377 
    Details
    ISSN: 1573-4870
    Keywords: Zirconia ; oxidation ; preparation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract This paper reports surface electrical properties of zirconia studied using work function measurements in the temperature range 297–1173 K during oxidation. It was found that surface preparation procedures, such as grinding and polishing, result in a change of its reactivity with oxygen. The effects produced by the preparation can be removed during thermal treatment at 1473 K.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1021820720142
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  • 13
    Electronic Resource
    Electronic Resource
    Oxidation of Calcium Boride at High Temperature (1998)
    Springer
    Journal of materials synthesis and processing 6 (1998), S. 407-410 
    Details
    ISSN: 1573-4870
    Keywords: CaB6 ; oxidation ; weight gain ; calcium borate ; oxidation resistance
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract The oxidation of CaB6 powders at high temperatures was investigated. The sample oxidized at 873 to 973 K for 25 hours exhibited weight gain with increasing oxidation temperature; the oxidation proceeded in accordance with the parabolic law during the initial oxidation stage. On the other hand, the weight gain of the sample oxidized at and above 1073 K for 4 h was approximately 80%; however even if the oxidation time was prolonged, an additional weight change did not occur. Based on the results of the X-ray diffraction analysis, calcium borate (CaB4O7) was present on the surface of the sample oxidized at 1073 K. The sample showed a good oxidation resistance at 1273 to 1373 K, because the surface film of calcium borate (CaB2O4) formed by oxidation acted as an oxidation resistant layer.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1021880906030
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  • 14
    Electronic Resource
    Electronic Resource
    High-temperature oxidation kinetics of Cu-Si alloys containing up to 4.75 wt.% Si in $$p_{{\text{O}}_{\text{2}} } $$ =0.01 atm and pure CO2 (1978)
    Springer
    Oxidation of metals 12 (1978), S. 323-329 
    Details
    ISSN: 1573-4889
    Keywords: Cu-Si alloys ; oxidation ; kinetics ; silica
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract The oxidation of Cu-Si alloys (containing up to 4.75 wt. % Si) in $${\text{p}}_{O_2 } $$ =0.01 atm from 800 to 1000°C has been investigated using thermogravimetry and other techniques. A 0.04% Si alloy followed a parabolic oxidation law with a rate similar to that of pure Cu. As the Si concentration increased the rate decreased and became irregular owing to SiO2 particles or flakes at the alloy-scale interface. It is considered that sintering of SiO2 particles and rupture of the sinter because of contraction during sintering are responsible for the irregular kinetics. A SiO2 layer forms directly on the 4.75% Si alloy which oxidizes uniformly. The SiO2 was always amorphous. In pure CO2 a similar pattern of amorphous SiO2 particles, flakes, and layers occurs.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00603576
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  • 15
    Electronic Resource
    Electronic Resource
    High-temperature corrosion and creep of Ni-Cr-Fe alloys in carburizing and oxidizing environments (1978)
    Springer
    Oxidation of metals 12 (1978), S. 387-404 
    Details
    ISSN: 1573-4889
    Keywords: carburization ; oxidation ; austenitic Fe-Ni-Cr alloys ; internal carbide formation ; high-temperature corrosion and creep
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract The carburization of NiCr 32 20 and NiCrSi 60 16 has been studied in CH4-H2 mixtures in the temperature range 900–1100°C. The methods included thermogravimetric measurements and studies on reacted specimens by X-ray diffraction, metallographic, and chemical analysis. Upon carburization internal carbides M7C3 and M23C6 are formed (M=mainly Cr); the rate of carburization is determined by carbon diffusion in the Fe-Ni matrix with carbide precipitations. The effect of the alloying elements Ni and Si on the carburization resistance of austenitic alloys is explained. By the same methods the oxidation and carburization in CO-H2O-H2 mixtures have been studied. The important role of a stable chromium oxide layer for the carburization resistance was confirmed. Creep tests at 1000°C in a CO-H2O-H2 atmosphere where Cr2O3 is stable showed carburization occurring through cracks in the oxide layer. At high strain rates premature failure occurs by carburization, which is followed by internal oxidation and formation of cracks, voids, and holes.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00612086
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  • 16
    Electronic Resource
    Electronic Resource
    Oxidation of a Ni-Cr-Al alloy at 850°C in air containing HCl gas (1978)
    Springer
    Oxidation of metals 12 (1978), S. 451-471 
    Details
    ISSN: 1573-4889
    Keywords: HCl gas ; H2O vapor ; Ni-Cr-Al alloy ; oxidation ; hot corrosion
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract Moist air containing HCl gas caused the oxide formed on a Ni-Cr-Al alloy at 850°C to crack during the early stages of growth, and extensive blistering and spalling occurred on cooling. In dry air containing HCl gas no oxide cracking was observed at temperature although the oxide blistered and spalled on cooling. In dry or moist air free from HCl an adherent protective oxide formed which did not spall on cooling. The oxide cracking at temperature has been attributed to the production of hydrogen by reaction of Cr and Al in the alloy with water vapor and the removal of NiO as NiCl2 by reaction with HCl gas. Hydrogen produced by reaction of water vapor or HCl with Cr or Al dissolved in the alloy at temperature, but on cooling the hydrogen was released, causing the oxide to blister and spall. Preoxidation of the alloy in HCl-free atmospheres eliminated these effects of HCl gas in short-term isothermal tests.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00612090
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  • 17
    Electronic Resource
    Electronic Resource
    High-temperature corrosion of nickel in SO2 (1978)
    Springer
    Oxidation of metals 12 (1978), S. 503-526 
    Details
    ISSN: 1573-4889
    Keywords: nickel ; sulfur dioxide ; oxidation ; sulfidation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract The reaction of nickel with SO2 has been studied in the temperature range 650–1100°C at SO2 pressures from 10 to 760 Torr. Reaction kinetics have been studied by thermogravimetry; the reacted specimens have been characterized by means of metallography, scanning electron microscopy, and electron microprobe analysis. The reaction involves oxidation and sulfidation except at sufficiently high temperatures and low pressures of SO2 (e.g., 1000°C and 10 Torr SO2) where only formation of NiO takes place. Approximately linear reaction kinetics are observed between 650 and 900°C. Reaction mechanisms are discussed, and the relative importance of oxide formation and sulfidation is interpreted in terms of the thermodynamics of the Ni-O-S system.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00603807
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  • 18
    Electronic Resource
    Electronic Resource
    The oxidation of copper studied by electron scattering techniques (1979)
    Springer
    Oxidation of metals 13 (1979), S. 331-351 
    Details
    ISSN: 1573-4889
    Keywords: oxidation ; copper ; thin films ; electron microscopy ; electron diffraction
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract The oxidation of thin single-crystal (100) and (111) films of copper at pressures of around 10−5 Torr and temperatures of 400 to 700°C has been observed by medium-energy electron diffraction, scanning electron microscopy, scanning and conventional microscopy using diffracted electron beams in the reflection mode, transmission electron microscopy, and transmission electron diffraction. Epitaxed nuclei of oxide are observed to grow into very thin single-crystal plates, using oxygen previously trapped in the copper film. There is considerable diffusion of the copper film. There is considerable diffusion of the copper away from the oxide. Between the oxide crystallites the copper surfaces appear to be unoxidized. A mottled contrast of the diffracted beam images of the copper surface is shown to result from many-beam dynamical diffraction effects.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00609304
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  • 19
    Electronic Resource
    Electronic Resource
    The high-temperature oxidation resistance of iron-silicon-aluminum alloys (1976)
    Springer
    Oxidation of metals 10 (1976), S. 277-289 
    Details
    ISSN: 1573-4889
    Keywords: alloy ; iron ; aluminum ; silicon ; oxidation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract Silicon or chromium can be used as an oxygen getter in iron-aluminum alloys to prevent the internal oxidation of aluminum. This suppresses the formation of the iron oxide nodules that tend to destroy binary iron-aluminum alloys during high-temperature oxidation. Alloys of iron containing aluminum and silicon in varying proportions were heated in flowing air for 50 hr at 1093°C. Of the alloys tested, one containing 6% aluminum and 1 % silicon was the most resistant to oxidation.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00618248
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  • 20
    Electronic Resource
    Electronic Resource
    Microstructures of the scales formed on zircaloy-4 in steam at elevated temperatures (1976)
    Springer
    Oxidation of metals 10 (1976), S. 255-276 
    Details
    ISSN: 1573-4889
    Keywords: Zircaloy-4 ; zirconium ; alloy ; oxidation ; microstructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract The ZrO 2 scales formed on Zircaloy-4 PWR tubes during corrosion in steam in the temperature range of 1000–1300°C have been found to contain a metallic phase that is relatively rich in Sn. The precise composition of the metallic phase has not been determined. Most of the metallic phase is located in a line of metallic particles, which is oriented parallel to the alloy-scale interface and located near the center of the scale. The exact morphology of the scale on either side of the particle line has not been identified. The oxide between the metallic particles and the scale-steam interface contains very little Sn, except for a narrow zone adjacent to the scale-steam interface, which was formed in the beginning of the reaction. It appears that the scale between the metallic particles and the alloy-scale interface consists of thin columnar grains of ZrO 2 with a very fine metallic phase probably located at the ZrO 2 grain boundaries. The experimental evidence presently available indicates that the metallic phase exists in the scales at the reaction temperature. If the metallic particles were rich enough in Sn, then a liquid metallic phase would exist in the oxide during the reaction. Kinetic studies demonstrate that these particles move with respect to the scale-steam interface toward the center of the alloy during the course of the oxidation reaction. It appears that the presence of the line of metallic particles could, under certain conditions, markedly influence the mechanical properties of the oxide scales formed on Zircaloy-4.
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    URL: http://dx.doi.org/10.1007/BF00618247
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    Defect structure in CoO (1976)
    Springer
    Oxidation of metals 10 (1976), S. 311-327 
    Details
    ISSN: 1573-4889
    Keywords: defect structure ; CoO ; oxidation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract The total concentration of point defects and deviation from stoichiometry in Co1-yO have been determined experimentally as functions of temperature and equilibrium oxygen pressure in the temperature range 1000–1250°C and oxygen pressure range 10−3-1 atm. This total concentration of defects has also been calculated from known values of the coefficients of chemical diffusion and tracer self-diffusion of cobalt. The results of the two methods agree well. It has been found in the investigated range of temperature and oxygen pressure that the defect structure of cobaltous oxide is composed not only of defects due to deviation from stoichiometry, singly ionized cation vacancies, and an equivalent amount of electron holes, but also of intrinsic defects, probably of the Frenkel type.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00612029
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    The influence of platinum on the maintenance of α-Al2O3 as a protective scale (1976)
    Springer
    Oxidation of metals 10 (1976), S. 341-345 
    Details
    ISSN: 1573-4889
    Keywords: α-Al2O3 ; platinum ; oxidation ; adhesion
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract The influence of externally located platinum on the isothermal stability of α-Al2O3 scales formed at high temperatures has been examined. It has been observed that a nickel-base alloy forms an external scale of α-Al2O3 during oxidation at 1200°C, but this scale breaks down isothermally, enabling a faster-growing Cr2O3-rich scale to develop. However, in the presence of platinum metal alongside the specimen in the furnace hot zone, the breakdown of the α-Al2O3 scale is postponed for a substantial period of time. It appears that platinum, as the volatile species PtO2, is incorporated into the growing α-Al2O3 scale where it either influences the stress relief mechanism at temperature or reduces oxidation growth stress generation and thus significantly enhances the isothermal stability of the scale.
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    URL: http://dx.doi.org/10.1007/BF00612031
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    Observations on the oxidation behavior of Ni-Cr alloys containing minor additions of group III, IV, or V elements (1976)
    Springer
    Oxidation of metals 10 (1976), S. 347-359 
    Details
    ISSN: 1573-4889
    Keywords: oxidation ; nickel-chromium alloys ; Group III–V elements ; reactive minor additions
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract The corrosion of a number of experimental ternary Ni-15 wt. % Cr-0.5wt. %X alloys (where X= Y, La, Ce, Sm, Th, U, Zr, or V) has been assessed in pure oxygen at 900° C for periods of exposure up to 450 hr, and compared with the behavior of an Ni-15% Cr control alloy. It has been established that while all of the alloys oxidize in accordance with a protective, approximately parabolic regime, considerable differences in oxidation rates are exhibited. In particular, additions of La, Ce, and Th bring about progressively enhanced rates of oxidation relative to the binary alloy, whereas Y, Sm, V, U, and Zr effect increasingly reduced rates of oxidation in the order given. The rate constant for the Th-bearing alloy is about two orders of magnitude larger than that for the alloy containing Zr. Such differences in behavior seem to be associated with subtle variations in the morphology/composition of the corrosion products from alloy to alloy. The observations are considered in the light of earlier published literature concerning the effects of rare-earth and other reactive elements on the oxidation behavior of Ni/Cr alloys.
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    URL: http://dx.doi.org/10.1007/BF00612047
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    Electron re-emission Mössbauer study of the oxidation of metallic iron in oxygen (1976)
    Springer
    Oxidation of metals 10 (1976), S. 377-401 
    Details
    ISSN: 1573-4889
    Keywords: oxidation ; iron ; Mössbauer ; electron re-emission ; ERM spectroscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract The results of an electron re-emission Mössbauer (ERM) spectroscopy study of the oxidation of metallic Fe at temperatures from 150 to 500°C in pure oxygen ( $${\text{p}}_{{\text{O}}_{\text{2}} } \approx {\text{ }}10$$ Torr) are presented. The oxidized samples were prepared from a metallic Fe sample enriched to 70% in the Mössbauer isotope Fe57 and the oxidation kinetics were determined volumetrically. Scanning electron microscopy was employed to characterize the morphology of the oxide films. The hematite, magnetite, and total-oxide thicknesses were determined from the ERM spectra using a theory recently developed in this laboratory, and the results were found to agree well with the measured oxygen content of the oxide films. For Fe and Fe-base alloys it is shown that the ERM technique is most useful in the oxide-thickness range of approximately 20–3000 Å within that range, oxide-phase identifications and thickness determinations are perhaps more readily determined by ERM spectroscopy than by any competing technique. In particular, the ERM measurement is nondestructive, and no supplementary measurements (such as surface-roughness determinations) or special sample preparations (such as oxide-film stripping) are required
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00612049
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    The diffusional growth of a scale with variable composition, diffusivity, and molar volume (1977)
    Springer
    Oxidation of metals 11 (1977), S. 57-62 
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    ISSN: 1573-4889
    Keywords: oxidation ; scale growth
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract Equations are presented to modify the classical theoretical expressions for the parabolic rate constant for the case in which the scale has a large composition range and a large variation in molar volume. The modifications appear as simple averages, together with a factor f.Evaluation of f for some hypothetical cases shows that it is near unity unless the composition gradient has an extreme deviation from linearity.
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    URL: http://dx.doi.org/10.1007/BF00611602
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  • 26
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    Behavior of oxide films on high-temperature alloys in carbonaceous gas atmospheres (1977)
    Springer
    Oxidation of metals 11 (1977), S. 23-56 
    Details
    ISSN: 1573-4889
    Keywords: oxidation ; carburization ; carbonaceous gases ; superalloys ; stainless steels ; film formation ; structure of oxide scales ; preoxidation ; metal dusting
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract Formation and deterioration of oxide films on several contemporary high-temperature alloys was studied in various carbonaceous gas atmospheres. Scanning electron microscopy and metallographic examination were applied to films on Fe-Cr-Ni and Ni-Cr-Al type alloy compositions exposed in CH 4/H2 and CO/CO2 atmospheres at temperatures up to 900° C and pressures up to 900 psi (6.2 × 106 N/m2). The effects of various preoxidation treatments were evaluated. Reduction of certain oxide phases is observed to promote catalytic gas decomposition. Al2O3 components in the films are observed to be stable under the reducing conditions experienced. Carbon uptake by various alloys is found to be quite sensitive to surface finish, with an observed increase in penetration with surface roughness.
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    URL: http://dx.doi.org/10.1007/BF00611601
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    The effect of ΔT (oxidizing temperature minus cooling temperature) on oxide spallation (1977)
    Springer
    Oxidation of metals 11 (1977), S. 91-106 
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    ISSN: 1573-4889
    Keywords: oxidation ; cyclic ; spallation ; stress
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract Several alloys (one iron base and five nickel base) were cyclically oxidized in a series of tests in which the higher temperature (1100 or 1200° C) of the cycle was fixed at a level to allow ample oxidation in reasonable time and the lower temperature was variable to allow cycle temperature differences (ΔT s ) of up to 1400°C. The alloys oxidized included those which formed simple oxides such as Al2O3 or Cr2O3, as well as those which formed complex scales. Cooling rates were relatively low to minimize thermal shock effects. Each cycle consisted of 1 hr at the higher temperature and 1/2 hr at the lower temperature. Samples were tested up to 370 cycles. The extent of attack was determined by specific weight change which was continuously monitored. For all nickel alloys, as ΔT increased the extent of spallation increased. This effect was attributed to thermal expansion mismatches between the oxide and the nickel substrate. The FeCrAl alloy was not sensitive to ΔTand resisted spalling at ΔT levels to 1400°C. FeCrAl, and the Al2O3 scale which forms on it, have thermal expansion coefficients which are substantially more alike than any of the other oxide-metal combinations tested.
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    URL: http://dx.doi.org/10.1007/BF00612137
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    The oxidation behavior of dilute Ni-V alloys at 1200°C (1977)
    Springer
    Oxidation of metals 11 (1977), S. 109-125 
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    ISSN: 1573-4889
    Keywords: nickel-vanadium ; oxidation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract The oxidation behavior of nickel and dilute Ni-V alloys has been studied in flowing oxygen at 1 atm pressure, using various kinetic and electron-optical techniques. The oxidation rate rises progressively as the alloy vanadium content is increased from 0 to 0.8% and then to 1.7%. However, further additions to 4.2% cause only a slight further increase. These increases in oxidation rate are largely controlled by the extent of doping of the NiO, particularly for the two more dilute alloys, although internal oxidation, spinel blocking effects in the oxide, and dissociation of the NiO affect the weight gains to some extent, particularly for the case of the Ni-4.2% V alloy.
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    URL: http://dx.doi.org/10.1007/BF00606398
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    The scaling behavior of a monophase Cu-3.36 wt.% Co Alloy at 700–1000°C (1981)
    Springer
    Oxidation of metals 16 (1981), S. 277-294 
    Details
    ISSN: 1573-4889
    Keywords: Binary alloys ; copper-cobalt ; oxidation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract The oxidation of a dilute copper-cobalt alloy at high temperatures has been studied to examine the effect of the cobalt addition on the different aspects of copper oxidation. The alloy oxidizes parabolically with a rate constant generally smaller than that of pure copper but approaching it at higher temperatures. The scale is essentially composed of copper oxides (CuO is observed only at 700°C) containing a small concentration of dissolved cobalt and particles of CoO in the inner region of the scale while internal oxidation is observed at all temperatures. The oxidation behavior of the alloy is examined with reference to the known factors affecting the corrosion of binary alloys. A theoretical calculation of the parabolic rate constant for pure copper and for the alloy with cobalt is also presented. Possible reasons for the observed deviation from the effect of doping as predicted on the basis of a simple model for the defect structure of Cu2O are pointed out.
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    URL: http://dx.doi.org/10.1007/BF00603837
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    Oxidation of Fe-C alloys in the temperature range 600–850°C (1981)
    Springer
    Oxidation of metals 16 (1981), S. 339-353 
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    ISSN: 1573-4889
    Keywords: Iron-carbon ; oxidation ; decarburization
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract The oxidation behavior of Fe-C alloys in the temperature range 600–850°C has been studied. CO 2 evolved during oxidation was measured using an infrared gas analyzer. The presence of C lowers the oxidation rate relative to that of pure Fe and this has been related to the rejection of carbon at the alloy-scale interface causing poor contact between scale and alloy. As a result, the scale contains a higher proportion of magnetite, which reduces its overall growth rate. Very little carbon is lost to the atmosphere. The ease with which the rejected carbon is incorporated into the alloy depends on the alloy structure.
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    URL: http://dx.doi.org/10.1007/BF00611348
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    High-temperature oxidation of titanium silicide coatings on titanium (1982)
    Springer
    Oxidation of metals 17 (1982), S. 43-54 
    Details
    ISSN: 1573-4889
    Keywords: Coatings ; oxidation ; titanium silicide ; kinetics
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract Coatings of Ti 5Si3 on titanium have been prepared by means of decomposition of silane SiH4 on heated titanium ribbons. Oxidation of the coated titanium specimens was much slower than that of the noncoated ones. Gravimetric and morphological experiments allowed to propose a mechanism describing the oxidation process.
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    URL: http://dx.doi.org/10.1007/BF00606192
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    An evaluation study of aluminide and chromoaluminide coatings on IN-100 (1982)
    Springer
    Oxidation of metals 17 (1982), S. 27-41 
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    ISSN: 1573-4889
    Keywords: aluminide coatings ; oxidation ; hot corrosion
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract Aluminide diffusion coatings are commonly used to protect aircraft gas turbine blades and vanes from oxidation and hot-corrosion attack. These coatings are based on NiAl intermetallic compound with other alloying elements like Cr and Ti either diffused from the superalloy substrate or incorporated in a separate coating step. The present investigation is mainly concerned with the development of both aluminide and chromoaluminide coatings on IN-100, a cast Ni-base superalloy. The coating structure and composition have been characterized and the cyclic oxidation and hot corrosion properties have been evaluated for the different types of coatings. The difference in the hot-corrosion properties between the aluminide and the chromoaluminide coatings has been rationalized in terms of the coating chemistry. The mode of coating degradation under hot-corrosion conditions has also been analyzed.
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    URL: http://dx.doi.org/10.1007/BF00606191
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    Kinetics and mechanisms of the oxidation of cobalt at 600–800°C (1982)
    Springer
    Oxidation of metals 17 (1982), S. 55-76 
    Details
    ISSN: 1573-4889
    Keywords: oxidation ; cobalt ; diffusion ; grain boundaries ; Co3O4
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract Two-phase layered scales comprising CoO and Co 3O4 formed on cobalt during oxidation at 600°, 700°, and 800°C and at oxygen partial pressures in the range 0.001–1 atm. The kinetics, which were obtained by thermogravimetric analysis, obeyed a parabolic rate law after an initial, non-parabolic stage of oxidation. The monoxide consisted of relatively large grains (∼10 μ) and the spinel comprised small grains (⪝3 μ) for all conditions of oxidation. Grain boundary diffusion of cations played a significant role in the growth of the spinel layer. Thermogravimetric data and the steady-state ratio of the oxide layer thicknesses were employed to calculate the rates of thickening of the individual oxide layers and the rate of oxidation of CoO to Co3O4.
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    URL: http://dx.doi.org/10.1007/BF00606193
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    Reflectance spectroscopy of oxide films. II. Oxide layers on chromium metal (1982)
    Springer
    Oxidation of metals 17 (1982), S. 157-176 
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    ISSN: 1573-4889
    Keywords: reflectance spectroscopy ; chromium ; oxidation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract Infrared reflectance spectra of oxidized chromium are presented as the first of a series of investigations of the reflectance spectra of oxidized materials. The spectra agree well with the behavior predicted in an earlier note, and confirm that simultaneous identification and thickness measurements of corrosion films are possible using this technique. The most prominent features for identification purposes are absorption bands at 610, 540, and 440 cm −1 for films ⪝1.5-μ thick, and at 610 and 300 cm−1 for thicker films. These bands are discernable despite the complicated effects introduced by interference fringes in the low-energy spectral region.
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    URL: http://dx.doi.org/10.1007/BF00606198
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    Application of the Rosenburg kinetic method for determination of the parabolic rate constants for metal oxidation (1978)
    Springer
    Oxidation of metals 12 (1978), S. 139-156 
    Details
    ISSN: 1573-4889
    Keywords: Rosenburg method ; oxidation ; CoO
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract The Rosenburg continuous kinetic method is proposed for the determination of the parabolic rate constants of metal oxidation as a function of temperature and oxidant pressure. Using this method, it is possible to make numerous measurements in a continuous manner on a single metal sample left in situ in the furnace, thus eliminating systematic errors due to differences between samples. Moreover, using this method it is possible to determine directly from a given kinetic curve such important parameters as the coefficients of chemical diffusion and self-diffusion of the more mobile species in the studied compound and the total equilibrium defect concentration. The latter parameter has been inaccessible up to now by the experimental method. The limits of applicability of this method are given in the paper. As an example of this method, the kinetics of cobalt oxidation are investigated in the range of temperature 1000–1250°C and oxygen pressure 10−3−1 atm; the results compare favorably with those obtained by other authors. The method is, however, applicable to certain other systems, namely, metal oxides and sulfides.
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    Corrosion of iron-, nickel-, and cobalt-base alloys in atmospheres containing carbon and oxygen (1982)
    Springer
    Oxidation of metals 17 (1982), S. 235-262 
    Details
    ISSN: 1573-4889
    Keywords: Carburization ; oxidation ; Fe alloys ; Ni alloys ; Co alloys
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract The corrosion of iron-, nickel-, and cobalt-base alloys has been studied in atmospheres containing carbon and oxygen in the temperature range 894–1366 K. It was observed that preformed Cr2O3 films are not effective barriers to carbon transport in atmospheres in which the oxide is not stable but that stable, growing Cr2O3 films are excellent barriers to carbon penetration. The presence of Fe-containing oxides on Fe-Ni-Cr and Fe-Cr alloys cause the scales to be permeable to carbon. This phenomenon was found to be sensitive to alloy surface preparation. Carbon transport through oxide scales may occur by two mechanisms: diffusion or molecular transport through physical defects. The present work has evidence of the latter but cannot rule out the former in cases where the carbon activity is sufficiently large. In gases containing CO and CO2 in which Cr carbide is stable Cr2O3 was found to form at the carbide-alloy interface by oxygen transport through the carbide. In A-CH4 Fe-Ni-Cr were found to undergo graphitization attack. The results were consistent with the formation and subsequent decomposition of metastable carbides, as proposed by Hochmann.
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    An investigation of pack-aluminide coating on steel (1982)
    Springer
    Oxidation of metals 17 (1982), S. 391-405 
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    ISSN: 1573-4889
    Keywords: Aluminide coating ; steel ; diffusion ; oxidation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract Aluminide coatings are known to protect steels from oxidation and corrosion in hydrocarbon and sulfur-bearing atmospheres. Pack cementation is ideally suited for forming these coatings on small intricate components, wherein a diffused layer is formed which is well bonded to the substrate. Even though pack aluminide coated steels are being commercially used, there has not been any systematic investigation of the factors that control the coating formation. The present investigation has been carried out to define the boundary conditions under which diffusion in the solid phase determine the coating kinetics. The effect of pack activity and temperature on the structure and kinetics of aluminde layer formation on EN-3 steel has been investigated. The coating characteristics were evaluated by metallography, EPMA, X-ray diffraction, and scanning electron microscope (SEM). Oxidation resistance of the coated samples were compared to that of 304 stainless steel after heating in air at 900°C for 72 h. The surface aluminum composition was found to be about 20% by weight which remained constant with time in the temperature range of 750°C–900°C. Weight gains and layer thicknesses obeyed parabolic relationship with time at all temperatures. Under these conditions, the system constitutes a vapor-solid diffusion couple. Interdiffusion coefficient $$(\tilde D)$$ values in the Fe-Al system have been determined, and the activation energy has been calculated to be 57 Kcals/mole, which agrees well with the literature values.
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    Oxidation of titanium modified type 310 stainless steel in low oxygen partial pressure atmospheres (1982)
    Springer
    Oxidation of metals 17 (1982), S. 415-427 
    Details
    ISSN: 1573-4889
    Keywords: Corrosion ; oxidation ; stainless steel ; coal gasification
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract A series of modified type 310 stainless steels containing 3 wt.% titanium were oxidized in a low oxygen partial pressure atmosphere ( $$P_{O_2 }$$ ≃3.8× 10 −15 atm) at 1255 K (1800°F). The scale morphologies and growth rates were similar to those observed on the same alloys in coal gasification atmospheres. The presence of sulfur (as H 2 S) in the gasification atmosphere apparently has a minimal effect on the corrosion scale formed. The growth rate and phase transformations of the external titanium-rich layer indicate that both titanium and manganese can readily permeate through the apparently compact Cr 2 O 3 layer.
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    URL: http://dx.doi.org/10.1007/BF00742121
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    The influence of superficially applied oxide powders on the high-temperature oxidation behavior of Cr2O3-forming alloys (1982)
    Springer
    Oxidation of metals 18 (1982), S. 55-81 
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    ISSN: 1573-4889
    Keywords: Nickel-chromium alloys ; iron-chromium alloys ; oxidation ; cerium oxide ; magnesium oxide
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract The effects of superficially applied CeO2, mixed rare earth oxides, Co3O4, and Cr2O3 powders on the isothermal and cyclic oxidation of Ni-Cr alloys and the effects of CeO2 and MgO powders on the isothermal oxidation of Fe-25 wt.% Cr have been studied over the temperature range 940–1150°C in pure oxygen and dry air. The rates of oxidation of both the Ni- and Fe-base alloys were markedly reduced by the application of CeO2 powder. The presence of CeO2 also improved the scale adherence and resulted in marked changes in the oxidation morphology. The presence of Co3O4 or Cr2O3 powders on Ni-Cr alloys or MgO on Fe-Cr also produced changes in the oxidation morphology but did not decrease the rate of oxidation. These results are interpreted in terms of the influence of the oxide powders on the development of scale microstructure and their effectiveness in decreasing grain boundary transport in Cr2O3.
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    Effect of creep on the oxidation characteristics of Fe-Si alloys at 973–1073 K (1982)
    Springer
    Oxidation of metals 18 (1982), S. 115-126 
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    ISSN: 1573-4889
    Keywords: Iron-silicon ; oxidation ; creep ; scale morphology
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract Studies of the simultaneous creep and oxidation of Fe-1Si and Fe-4Si alloys at a constant tensile stress of 16 N· mm−2 at 973–1073 K have shown that scales formed at oxygen partial pressures of 20–1013 mbar were thicker by a factor of 2 than those formed on uncrept specimens. Scales on uncrept alloys comprised alternate layers of wustite and fayalite, whereas scales on crept alloys exhibited an additional external layer of magnetite. Only intergranular oxidation (fayalite) was observed in uncrept alloys, but crept alloys showed both intra- and intergranular oxidation (silica). Uniquely nodular scales were formed only on the Fe-4Si alloy on crept and uncrept specimens. Oxidized, uncrept Fe-1Si showed a fine-grained ferrite substrate which was absent in the crept alloy. It is believed that oxide growth stresses stimulated a recrystallization process.
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    URL: http://dx.doi.org/10.1007/BF00662033
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    The influence of an intermediate annealing treatment on the oxidation of copper and nickel (1980)
    Springer
    Oxidation of metals 14 (1980), S. 187-205 
    Details
    ISSN: 1573-4889
    Keywords: oxidation ; annealing ; NiO ; Cu2O ; cation vacancy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract A study has been made of the effects of an intermediate, isothermal annealing treatment in argon on the oxidation kinetics of copper and nickel in 1 atm oxygen at 800 and 1100°C, respectively, using a semiautomatic microbalance. Changes in scale morphology and composition have been investigated using various physical techniques. The outer CuO layer formed on copper during oxidation dissociates very rapidly on annealing to give CU2O and oxygen since the partial pressure of oxygen in the gas is below the dissociation pressure of CuO but above that of Cu2O at 800°C. The CuO layer is quickly re-formed on reoxidation in oxygen. There are relatively few other changes in the oxide morphologies of either metal during annealing, although the small grains present in the scale adjacent to the metal after oxidation are able to grow. During reoxidation both metals show a reduction in oxidation rate constant because of the decrease in total cation vacancy concentration in the scale and the reduced cation vacancy gradient across the scale brought about by the reduction in oxygen partial pressure at the oxide-gas interface during annealing. The reoxidation rate constants following annealing approach those recorded prior to annealing as the equilibrium cation vacancy levels in the scales are reestablished in the oxidizing environment. Rosenberg's method for analysis of the kinetics of reoxidation has enabled the equilibrium concentrations and diffusion coefficients of cation vacancies in CU2O and NiO during oxidation in 1 atm oxygen at the appropriate temperatures to be estimated approximately. These show reasonable agreement with literature values.
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    Correlation between the oxidation mechanism of titanium under a pure oxygen atmosphere, morphology of the oxide scale, and diffusional phenomena (1980)
    Springer
    Oxidation of metals 14 (1980), S. 249-261 
    Details
    ISSN: 1573-4889
    Keywords: titanium ; oxidation ; oxide scale ; solid state diffusion ; kinetics
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract The oxidation behavior of titanium was studied over the temperature range of 600 to 800°C in a pure oxygen atmosphere. A parabolic kinetics period is made up of a succession of short parts whose weight gain is nearly constant and whose beginning is characterized by an alteration of the oxidation rate. The kinetics curve is closely correlated with the morphology of the oxide scale which contains several layers separated by short cracks. These cracks decrease the diffusional flows of oxygen and titanium and alter the oxidation rate. A parabolic-linear kinetics transition is attributed to the formation of a continuous crack between the oxide scale and the matrix. The oxide scale then forms a porous barrier of constant thickness which induces a linear rate law due to the steady-state oxygen diffusion. Titanium cannot diffuse across the continuous crack. During the linear kinetics period several layers of constant thickness, separated by a continuous crack, spread out.
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    URL: http://dx.doi.org/10.1007/BF00604567
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    The role of thermal shock in cyclic oxidation (1980)
    Springer
    Oxidation of metals 14 (1980), S. 325-336 
    Details
    ISSN: 1573-4889
    Keywords: oxidation ; cyclic ; spalling ; stress
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract The effect of thermal shock on the spalling of oxides from the surfaces of several commercial alloys was determined. The average cooling rate was varied from approximately 240°C/sec to less than 1.0°C/sec during cyclic oxidation tests in air. The tests consisted of 100 cycles of 1 hr at the maximimum temperature (1100 or 1200°C). The alloys were HOS-875, TD-Ni, TD-NiCrAl, In-601, In-702, and B-1900 plus Hf. All of these alloys exhibited partial spalling within the oxide rather than total oxide loss down to bare metal. Thermal shock resulted in deformation of the metal, which in turn resulted, in most cases, in change of the oxide failure mode from compressive to tensile. Tensile failures were characterized by cracking of the oxide and little loss, while compressive failures were characterized by explosive loss of platelets of oxide. This behavior was confirmed by examination of mechanically stressed oxide scales. The thermally shocked oxides spalled less than the slow-cooled samples with the exception of TD-NiCrAl. This material failed in a brittle manner rather than by plastic deformation. The HOS-875 and the TD-Ni did not spall during either type of cooling. Thus, the effect of thermal shock on spalling is determined, in large part, by the mechanical properties of the metal.
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    URL: http://dx.doi.org/10.1007/BF00603788
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    ESCA study of oxidation and hot corrosion of nickel-base superalloys (1980)
    Springer
    Oxidation of metals 14 (1980), S. 415-435 
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    ISSN: 1573-4889
    Keywords: oxidation ; hot corrosion ; ESCA ; superalloys ; sodium sulfate
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract A study of the high-temperature oxidation and Na2SO4-induced hot corrosion of some nickel-base superalloys has been accomplished by using ESCA to determine the surface composition of the oxidized or corroded samples. Oxidation was carried out at 900 or 1000°C in slowly flowing O2 for samples of B-1900, NASA-TRW VIA, 713C, and IN-738. Oxidation times ranged from 0.5 to 100 hr. Hot corrosion of B-1900 was induced by applying a coating of Na2SO2 to preoxidized samples, then heating to 900° C in slowly flowing O2. Corrosion times ranged from 5 min to 29 hr. For oxidized samples, the predominant type of scale formed by each superalloy was readily determined, and a marked surface enrichment of Ti was found in each case. For corroded samples, the transfer of significant amounts of material from the oxide layer to the surface of the salt layer was observed to occur long before the onset of rapidly accelerating weight gain. Some marked changes in surface composition were observed to coincide with the beginning of accelerating corrosion, the most striking of which were a tenfold decrease in the sulfur to sodium ratio and an increase in the Cr(VI) to Cr(III) ratio.
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    URL: http://dx.doi.org/10.1007/BF00603610
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    Comparison of the kinetics and morphologic properties of titanium, Ti-1.5Ni and Ti-2.5Cu during oxidation in pure oxygen between 600 and 820°C (1980)
    Springer
    Oxidation of metals 14 (1980), S. 471-498 
    Details
    ISSN: 1573-4889
    Keywords: oxidation ; titanium ; Ti-Ni alloy ; Ti-Cu alloy ; kinetics ; oxide scale ; solid-state diffusion
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract The kinetics and morphologic oxidation properties of titanium, Ti-1.5Ni and Ti-2.5Cu were compared. Titanium and Ti-1.5Ni have a similar behavior, concerning the kinetics and the oxide micro structure. Copper additions decrease the oxidation rate of titanium. The oxide scales formed on Ti-Cu are thinner and less cracked than those obtained on Ti or Ti-1.5Ni. Copper is found in the oxide scale of Ti-Cu, whereas nickel is not found in the oxide scale of Ti-Ni. The oxidation of titanium and its alloys is controlled chiefly by diffusional phenomena in the oxide scale. Thus the alterations of the oxide scale structure and the slower oxidation rate of Ti-2.5Cu can be attributed to the copper which diffuses towards the gas-oxide interface.
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    URL: http://dx.doi.org/10.1007/BF00603475
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    Influence of small Pt additions on Al2O3 scale adherence (1980)
    Springer
    Oxidation of metals 14 (1980), S. 517-530 
    Details
    ISSN: 1573-4889
    Keywords: CoCrAl ; oxidation ; oxide-scale adherence ; platinum ; rare-earth effects
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract The effects of small Pt additions (1 or 3 wt.%) on the oxidation behavior of Co-10Cr-11Al and a similar alloy containing Hf have been studied. An intermetallic phase was present in the alloy containing Hf and Pt but not in that containing Pt alone. The size and distribution of the intermetallic was comparable to that of similar alloys containing oxide dispersions produced by a controlled internal oxidation treatment. As a consequence it promoted the formation of inwardly growing Al2O3 pegs that helped key the surface scale to the substrate and improve the scale-metal adhesion in both isothermal and cyclic oxidation tests. The improvement in overall oxidation resistance relative to an addition-free alloy was considerable, and similar to that of the best oxide dispersion-containing alloys.
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    The ratios of layer thicknesses in a multiphase oxide scale (1984)
    Springer
    Oxidation of metals 22 (1984), S. 35-43 
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    ISSN: 1573-4889
    Keywords: oxidation ; multiphase oxides ; steam ; 9Cr steel ; hematite
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract The diffusion controlled oxidation of a metal to produce two-layer oxides and one type of three-layer oxide is analyzed. It is proved that the relative thicknesses of the oxide layers must tend to a limiting constant value for all oxidizing conditions. The analysis for the three-layer oxide is applied to the oxidation of 9Cr steel in high pressure steam at 500°C. The proportion of hematite expected within the outer oxide layers produced in steam with oxygen partial pressures ≥10−20 bar is calculated to be very dependent on the metal oxidation rate and not on the oxygen partial pressure.
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    URL: http://dx.doi.org/10.1007/BF00659247
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    Studies on the mechanism of high temperature corrosion of cobalt in SO2 atmospheres with the use of18O and35S isotopes (1984)
    Springer
    Oxidation of metals 22 (1984), S. 101-115 
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    ISSN: 1573-4889
    Keywords: cobalt ; oxidation ; sulfidation ; transport ; tracer ; autoradiographs
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract The composition and morphology of scales formed on cobalt in sulfur dioxide atmospheres (1.013 × 105 Pa) at 850 and 900°C and transport phenomena occurring in the growing scales have been investigated. The transport phenomena have been studied by the marker method and with the use of SO2 labeled with the oxygen isotope18O and sulfur isotope35S. The scales were composed of sulfide and oxide mixtures and grew due to the outward diffusion of cobalt and inward transport of SO2 molecules through the discontinuities in the scale. These molecules, as well as the oxidant originating from the dissociation of the outer scale layer, take part in the formation of the inner scale layer.
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    URL: http://dx.doi.org/10.1007/BF00656899
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    The oxidation behavior of the nimonic alloy PE16 in carbon dioxide at 700–800°C (1981)
    Springer
    Oxidation of metals 15 (1981), S. 231-249 
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    ISSN: 1573-4889
    Keywords: oxidation ; carburization ; nimonic alloy PE16 ; carbon dioxide
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract The oxidation behavior of the nimonic alloy PE16 in carbon dioxide has been examined, at 700–800° C, for periods up to 10,250 hr duration. At all temperatures the oxidation kinetics were pseudoparabolic. The chromium-rich and titanium-bearing oxide scale was adherent, except at 800° C, when ∼10% spalled. Intergranular oxidation beneath the outer scale resulted in the formation of alumina and to a lesser depth, titanium oxide. The penetration increased parabolically with time and also with temperature, the activation energy being 50 kcal/mole. After oxidation at all temperatures the carbon profiles across the oxidized alloys were determined by nuclear microprobe analysis and indicated three distinct regions. From the gas interface carbon was picked up increasingly in the oxide scale, with a peak concentration (0.1–0.34 wt. %) at the oxide-alloy interface. The carbon level then fell sharply and to the depth of the titanium-bearing intergranular oxide the alloy was decarburized. At this juncture carbon had entered the alloy to a maximum concentration of 0.23–0.50 wt. % and a depth which increased both with temperature and exposure. Carburization is attributed to a crevice corrosion mechanism.
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    Oxidation and hot corrosion of coated and bare oxide dispersion strengthened superalloy MA-755E (1981)
    Springer
    Oxidation of metals 15 (1981), S. 251-276 
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    ISSN: 1573-4889
    Keywords: oxide dispersion strengthening ; oxidation ; hot corrosion ; powder metallurgy ; porosity
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract Cyclic hot corrosion and oxidation testing of an experimental oxide dispersion strengthened (ODS) superalloy MA-755E were conducted in a hot gas stream at Mach 0.3. The response of the ODS alloy, bare or with protective coatings, was similar to that of a conventional cast alloy, IN-792, in hot corrosion at 900°C. However, during oxidation at 1100 and 1150°C the ODS alloy differed from the cast alloy by developing a greater amount of subsurface porosity. Compared with a diffused aluminide coating, an electron beam vapor deposited NiCrAlY coating offered superior oxidation protection and decreased porosity formation. In additional testing, the tendency to form porosity was associated with the large grains of recrystallized powder metallurgy alloys but was independent of the presence of an oxide dispersion.
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    Prediction of the chromium oxide oxidation rate from the equilibrium constants and the mass transfer coefficients at high temperatures (1981)
    Springer
    Oxidation of metals 15 (1981), S. 277-286 
    Details
    ISSN: 1573-4889
    Keywords: chromium oxide ; oxidation ; volatilization
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract Previously published experimental data on the oxidation/volatilization of chromium oxide covering a wide range of oxygen pressure (10−6 to 1 atm) and temperature (900 to 1385°C) were used to predict its oxidation rate from the equilibrium constants and the mass transfer coefficients using the kinetic model originally developed by Bartlett. The experimental data available were found to be either surface-reaction-controlled or volatile-product-controlled which are the limiting cases of the model. The availability of the dimensionless fluid correlations and the force constants for the diffusing species enabled the prediction of the mass transfer rate for the various sample shapes and hydrodynamic conditions. The good agreement between the experimental and predicted oxidation rates covered four orders of magnitude range.
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    Influence of metal grain growth on the oxidation behavior of a 25Cr-20Ni steel (1981)
    Springer
    Oxidation of metals 15 (1981), S. 485-493 
    Details
    ISSN: 1573-4889
    Keywords: oxidation ; air ; Cr-Ni steel ; grain growth
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract Comparative oxidation tests with a fine- and a coarse-grain 25Cr-20Ni steel, and cast steel of similar composition in synthetic air between 900 and 1300°C reveal a strong influence of grain growth in the base metal on the oxidation behavior. Metal grain growth destroys the protective Cr2O3-rich scale, and promotes the formation of a scale rich in iron oxides. The result is a higher scaling rate, and a higher Cr depletion at the metal-scale interface of the fine-grain material which undergoes grain growth during oxidation.
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    Penetration of sulfur through preformed protective oxide scales (1983)
    Springer
    Oxidation of metals 19 (1983), S. 37-52 
    Details
    ISSN: 1573-4889
    Keywords: oxidation ; sulfidation ; penetration
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract Thermodynamic assessment of sulfur penetration through otherwise protective scales such as Cr2O3, Al2O3 has been carried out for Co-Cr- and Co-Cr-Al-base alloys. Limiting conditions for sulfide formation following gas molecular transport and solution-diffusion transport have been established and the results partially confirmed by experiments carried out on Co-10Cr, Co-25Cr, and Co-10Cr-5Al alloys in sulfurous atmospheres. The results show that molecular transport of sulfurous gas species through the growing oxide scale definitely occurs. It was not possible to confirm or disprove the solutiondiffusion mechanism.
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    Numerical modeling of high-temperature corrosion processes (1995)
    Springer
    Oxidation of metals 44 (1995), S. 309-338 
    Details
    ISSN: 1573-4889
    Keywords: modeling ; numerical modeling ; numerical techniques ; finite-difference techniques ; oxidation ; corrosion ; carburization ; nitridation ; diffusion
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract Numerical modeling of the diffusional transport associated with high-temperature corrosion processes is reviewed. These corrosion processes include external scale formation and internal subscale formation during oxidation, coating degradation by oxidation and substrate interdiffusion, carburization, sulfidation and nitridation. The studies that are reviewed cover such complexities as concentration-dependent diffusivities, cross-term effects in ternary alloys, and internal precipitation where several compounds of the same element may form (e.g., carbides of Cr) or several compounds exist simultaneously (e.g., carbides containing varying amounts of Ni, Cr, Fe or Mo). In addition, the studies involve a variety of boundary conditions that vary with time and temperature. Finite-difference (F-D) techniques have been applied almost exclusively to model either the solute or corrodant transport in each of these studies. Hence, the paper first reviews the use of F-D techniques to develop solutions to the diffusion equations with various boundary conditions appropriate to high-temperature corrosion processes. The bulk of the paper then reviews various F-D modeling studies of diffusional transport associated with high-temperature corrosion.
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    Analytical techniques in high temperature corrosion (1995)
    Springer
    Oxidation of metals 44 (1995), S. 339-374 
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    ISSN: 1573-4889
    Keywords: analytical techniques ; Fe, Cr, Fe−Cr alloys, Ni, Al, β-NiAl ; oxidation ; transport processes
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract This paper considers the application of analytical techniques (particularly AES, SIMS, RHEED, laser Raman, Mössbauer, TEM, EELS) to high-temperature oxidation studies. Specific systems reviewed include NiO on Ni, oxides on Fe, Cr and their alloys, and Al2O3 on Al and β-NiAl. The often complementary information provided by the various techniques leads to a better understanding of oxide growth mechanisms on an atomic sale, interfacial segregation phenomena, and the role of reactive elements in modifying transport processes in oxides.
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    High-temperature corrosion in mixed gas environments (1995)
    Springer
    Oxidation of metals 44 (1995), S. 239-264 
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    ISSN: 1573-4889
    Keywords: oxidation ; carburization ; sulfidation ; scaling ; internal precipitation ; diffusion
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract Scaling reactions between pure metals and multiple oxidant gases are reviewed briefly. It is recognized that elemental oxidant activities are usually so low that the actual reactant species are heteronuclear molecules such as SO2, CO2, etc. The formation of duplex, sulfide-oxide scales on iron and manganese, even when sulfide is unstable with respect to oxide, is attributed to direct reaction with SO2. The persistence of the metastable sulfide is due to its preservation by the rapidly growing scale. The reaction of pure chromium with a number of mixed gases is also discussed. The continued formation of carbides and nitrides beneath an external Cr2O3 scale layer indicates that the latter material is permeable to gas species. Interaction among different gas species is observed, and is attributed to selective adsorption on internal surfaces within the chromium oxide. New work on the reaction of alloys with mixed gases is reported. Several austenitic heat-resistant alloys were exposed at 1000°C to gases containing one, two or all of the oxidants carbon, sulfur and oxygen. Gases containing two or more oxidants produced multiple zones of internal precipitation. The precipitates were chromium-rich oxides, sulfides and carbides arranged in order of thermodynamic stability: oxides beneath the external scale, carbides deepest within the alloys and sulfides in an intermediate zone overlapping the oxide zone. Each precipitate zone widened according to parabolic kinetics. This finding confirms the as yet untested prediction made by J. L. Meijering in 1971. However, the rate at which a particular zone grows changes according to presence of other oxidants. Interactions between the oxidants can be large and reaction rates are currently not predictable.
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    Corrosion of iron in sulfur dioxide at 0.1 MPa (1996)
    Springer
    Oxidation of metals 45 (1996), S. 469-486 
    Details
    ISSN: 1573-4889
    Keywords: iron ; sulfur dioxide ; oxidation ; tracer
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract The reaction of iron with sulfur dioxide at 0.1 MPa and 1073 K was studied. The composition and morphology of the scales, transport phenomena occurring in the growing scales, and kinetics of the process were investigated. Scanning electron microscopy and various techniques of X-ray analysis were used. The transport phenomena were studied by marker and by radiotracer techniques. The scales were composed of sulfide and oxides and grew by the outward diffusion of metal. It was concluded that the process initially took place through the reaction of iron with sulfur dioxide molecules. During the next stage of the process the reaction with sulfur dioxide molecules as well as with oxygen molecules is possible.
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    Reactive-element effect of electrodeposited Y2O3 oxide films on the oxidation of Fe−25Cr and Fe−25Cr−10Al alloys (1995)
    Springer
    Oxidation of metals 43 (1995), S. 217-236 
    Details
    ISSN: 1573-4889
    Keywords: oxidation ; reactive-element effects ; electrodeposition ; Y2O3 ; oxide film
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract Thin Y2O3 films were deposited by the electrochemical deposition-pyrolysis process on Fe−25Cr and Fe−25Cr−10Al alloys. The influence of the films on the oxidation behavior of the alloys was studied at 850°C and 1000°C. The results showed that Y2O3 films remarkably decreased the oxidation rate of Cr2O3-forming alloys and spallation of the scales, but they did not decrease the oxidation rate of the Al2O3-forming alloys, although they do reduce the spallation of Al2O3 scales. Y2O3 films remarkably change the morphology of the scales on both alloys, depending on the oxidation temperatures. These results show that the reactive-element effects of Y2O3 films on the Cr2O3 formers and Al2O3 formers are different.
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    Alloy-grain-size dependence of the effectiveness of silica coatings as oxidation barriers on stainless steel (1995)
    Springer
    Oxidation of metals 43 (1995), S. 263-277 
    Details
    ISSN: 1573-4889
    Keywords: Fe−Cr−Ni alloy ; oxidation ; silica ; spallation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract In order to determine the effect of alloy grain size on the oxidation properties of silica-coated austenitic Fe-18Cr-20Ni stainless steel, both coarse-grain (100-μm grain size) and fine-grain (5-μm grain size) forms of the alloy were produced. A 1-μm-thick vitreous silica coating was deposited by chemicalvapor deposition on the alloys, which were subjected to isothermal and cyclic oxidation in air at 900°C. The coarse-grain alloys underwent widespread oxidation below the silica coating, leading to extensive coating spallation. This was attributed to the inability of the alloy to supply a sufficient outward flux of chromium to prevent oxygen penetration through microcracks in the silica coating. Due to an abundance of chromium available at the surface of the finegrain alloy, chromia formed in the microcracks within the silica layer. As a result, the silica-coated, fine-grain alloy demonstrated superior oxidation resistance and excellent adhesion of the coating.
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    Oxidation behavior of copper at high temperatures under two different modes of direct-current applications (1995)
    Springer
    Oxidation of metals 43 (1995), S. 185-215 
    Details
    ISSN: 1573-4889
    Keywords: copper ; oxidation ; direct current ; uninterrupted mode ; interrupted mode
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract Oxidation kinetics of copper in the temperature range of 973–1173 K atP O 2=21.27 kPa exhibit enhancement and deceleration in the rates with changing polarity compared to normal oxidation under interrupted mode of directcurrent application. These conditions are achieved by connecting the oxidizing copper covered with an initially formed thin oxide film to the positive and negative terminal of a dc source, respectively. However, the influence of direction of the current is found to be opposite under uninterrupted mode of impressed current flow in the same temperature range. The effect of short-circuiting the metal to the outer oxide/air interface on the reaction kinetics is also reported. The rate of oxide-scale growth under normal condition, and two different modes of current applications as well as with shorting circuitry attachment conform to the parabolic growth law. The results pertaining to the two different modes of impressed current have been discussed considering both the phenomena of electrolysis of the oxide electrolyte and the polarization at the two phase boundaries. The enhancement and the reduction in rates under uninterrupted impressed current conditions are explained on the basis of increased and decreased average defect concentrations, respectively, within the oxide layer. The acceleration and deceleration in the rates under interrupted mode of current flow have been explained in the light of sustenance of a steeper and flatter electrochemical-potential gradient of defects, respectively, across the growing-oxide layer. The possible different responses of the metal/oxide and oxide/air interfaces to the impressed current brought into play by two different modes of current application, have enabled to display a better insight on the mechanistic aspects of scale growth under the influence of an externally applied current.
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    The influence of ceria surface additions on manganese oxidation at high temperatures (1995)
    Springer
    Oxidation of metals 43 (1995), S. 237-261 
    Details
    ISSN: 1573-4889
    Keywords: manganese ; oxidation ; ceria ; coating ; air ; low oxygen pressure ; high temperature ; manganosite ; transport mechanism ; iron ; CeFeO3 structure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract The kinetics, scale composition, and growth mechanism of ceria-coated and blank specimens of manganese oxidation in air were examined. The scale growth obeys the parabolic rate law at 700°C for all specimens. Lower parabolic rate constants for coated specimens are attributed to the presence of a CeO2 external scale. It constitutes a limiting factor of the oxygen activity at the gas-oxide interface. This lower-oxygen activity leads to a less-metal-deficient state of the scale. Due to this, the inner-MnO scale becomes more adherent to the substrate. Preheating at 700°C, in hydrogen (PO 2=10−24 atm), was performed in order to be placed in the MnO stability domain and try to introduce cerium in the manganese-oxide scale. This pretreatment promotes macroscopic bonding in the layer formed during subsequent oxidation in air. It ensures a better scale adherence. A new diffusional-transport mechanism in manganosite is proposed in accordance with all experimental observations of the literature and with the cerium-manganese-oxygen system studied in the present work. This model considers the high Mn3+ stability in octahedral sites of the MnO oxygen ion body. Low-oxygen partial pressure conditions permit the formation of an adherent inner-MnO scale on coated specimens. A CeO2 scale formed above the MnO scale; MnO is present as a minor component in this scale and it is located mainly at the internal interface. The difficulties in forming the cerium-orthomanganite are attributed to the very high stability of MnO related to this wide range of nonstoichiometry and to the low manganese diffusivity through the cerium-containing scale.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01047029
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    Comparison of classical oxidation and laser oxidation of a chromium PVD coating on a pure-iron substrate (1995)
    Springer
    Oxidation of metals 43 (1995), S. 279-300 
    Details
    ISSN: 1573-4889
    Keywords: oxidation ; chromium coating ; laser ; oxygen diffusion
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract The oxidation of a chromium PVD coating on pure iron by a continuous 5-kW CO2 laser beam in pure oxygen at 700°C for 20 min was compared with classical furnace oxidation. Laser oxidation induces faster oxidation kinetics, especially at the beginning of oxidation, without modifying the oxide nature (Cr2O3) and morphology. Oxygen-isotopic-exchange tests show that oxygen grain-boundary diffusion does not depend on the oxidation conditions, at least after 12 min oxidation. The effec of the laser treatment is discussed with respect to oxide nucleation, metastable-oxide formation, and oxide-formation-entropy evolution. The oxidation kinetics follow a parabolic law, and the oxide-growth mechanism was attributed to countercurrent oxygen and chromium diffusion along grain boundaries. Oxygen diffusion occurred by oxygen interstitials. The oxidation constant calculated from grain-boundary diffusion in the chromia scale is smaller than the experimental oxidation constant, suggesting the presence of particular short circuits (e.g., microcracks).
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01047031
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    Rehealing ability of oxide scales formed on microcrystalline K38G coatings (1995)
    Springer
    Oxidation of metals 43 (1995), S. 317-328 
    Details
    ISSN: 1573-4889
    Keywords: microcrystalline ; rehealing ; oxide scales ; superalloys ; coating ; oxidation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract The rehealing ability of the protective oxide scales formed on a microcrystalline coating of the Ni-base superalloy K38G has been studied. The results indicated that the oxide scales on the coating may be rehealed when the original scales are destroyed, and the coating still has excellent resistance against high-temperature oxidation. When the original Al2O3 oxide scales spall, mixed-oxide scales of both (Al, Cr)2O3 and TiO2 can form on the surface. The mixed scales are very protective and adherent.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01047033
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    Phase stability, oxidation, and interdiffusion of a novel Ni−Cr−Al−Ti−Si bond-coating alloy between 900 and 1100°C (1995)
    Springer
    Oxidation of metals 43 (1995), S. 329-352 
    Details
    ISSN: 1573-4889
    Keywords: Ni−Cr−Al−Ti−Si bond-coating alloy ; phase stability ; oxidation ; interdiffusion
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract A novel, low-expansion experimental Ni−Cr−Al−Ti−Si bond-coating alloy was investigated in the as-cast state concerning its phase stability, oxidation resistance in air, and interdiffusion with single-crystal IN-100 at 900, 1000, and 1100°C. Isothermal oxidative thermogravimetry was employed up to 500 hr. Interdiffusion was compared to a commercial Ni−Co−Cr−Al−Y alloy on IN-100. Oxidized Ni−Cr−Al−Ti−Si specimens and diffusion couples were characterized by metallography, SEM, EDX, XRD, and XRF. The Ni−Cr−Al−Ti−Si alloy provides good oxidation resistance in air at least up to 1000°C. The alloy is an alumina former. Due to its coarse microstructure, other oxides (e.g., rutile) may form and considerably dominate the oxidation behavior. The kinetics of oxidation were correlated with temperature, formation of phases, and morphology of oxides. Interdiffusion fluxes between Ni−Cr−Al−Ti−Si and IN-100 were mainly directed to the superalloy. They were faster than in Ni−Co−Cr−Al−Y/IN-100 diffusion couples.
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    URL: http://dx.doi.org/10.1007/BF01047034
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    Possible scaling modes in high-temperature oxidation of two-phase binary alloys. II: Low oxidant pressures (1995)
    Springer
    Oxidation of metals 43 (1995), S. 379-394 
    Details
    ISSN: 1573-4889
    Keywords: two-phase alloys ; oxidation ; scale structure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract The main possible modes of the high-temperature corrosion of binary two-phase alloys by a single oxidant under gas-phase pressures sufficient to corrode only the most-reactive alloy component are examined to compare their behavior with that of single-phase alloys. In the absence of important diffusion processes of the metal components in the alloy, the scale structures expected are different from those typical of single-phase alloys. Moreover, when diffusion in the alloy becomes important, these systems may develop an outer single-phase layer depleted in the most-reactive component, which may lead to different possible scale structures. The conditions for the transition between the various oxidation modes as well as the effect of the various parameters of kinetic, thermodynamic, and structural nature over the corrosion behavior of two-phase alloys are also examined.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01047037
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    The oxidation resistance of a sputtered, microcrystalline TiAl-intermetallic-compound film (1995)
    Springer
    Oxidation of metals 43 (1995), S. 395-409 
    Details
    ISSN: 1573-4889
    Keywords: microcrystalline film ; TiAl intermetallic compound ; oxidation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract The oxidation behavior of a cast TiAl intermetallic compound and its sputtered microcrystalline film was investigated at 700–900°C in static air. At 700°C, both the cast alloy and its sputtered microcrystalline film exhibited excellent oxidation resistance. No scale spallation was observed. However, at 800–900°C, the oxidation kinetics for the cast TiAl alloy followed approximately a linear rate law, which indicates that it has poor oxidation resistance over this temperature range. The poor oxidation resistance of TiAl was due to the formation of an Al2O3+TiO2 scale which spalled extensively during cooling. Nevertheless, the sputtered, TiAl-microcrystalline film exhibited very good oxidation resistance. The oxidation kinetics followed approximately the parabolic rate law at all temperatures. Although the composition of the scales was the same as that of scales formed on the cast alloy, the scales formed on the sputtered microcrystalline-TiAl film are adherent strongly to the substrate. No scale spallation was found at 700–850°C, while a small amount of spallation was observed only at 900°C. This indicates that microcrystallization can improve the oxidation resistance of the TiAl alloy.
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    URL: http://dx.doi.org/10.1007/BF01046890
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    Characterization of Ni-25 wt.% Cr alloys containing reactive elements and the oxide scales grown on them at high temperatures using transmission electron microscopy (1995)
    Springer
    Oxidation of metals 43 (1995), S. 435-457 
    Details
    ISSN: 1573-4889
    Keywords: oxidation ; reactive-element effect ; reactive-element oxysulfide ; reactive-element oxide ; reactive-element orthochromite
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract Nickel-base alloys of nominal composition Ni-25 Wt.% Cr-(0-0.6 Wt.%) RE (RE=Y, La, and Ce) were prepared by conventional arc-melting Ni, Cr, and Y metal. The microstructure of the alloys was characterized by using electron diffraction and X-ray energy dispersive spectroscopy (XEDS) to determine the structure, morphology, and distribution of second-phase particles. Selected alloys were oxidized at 900°C and 1000°C in 1-atm air, and the resultant oxide scales were characterized using the same analytical techniques. The experimentally determined electron-diffraction data were compared with a JCPDF-EDD database, and several compounds were matched. The observed phases were RE oxysulfide, cerium orthochromite-CeCrO3, yttria-Y2O3, yttrium orthochromite-YCrO3, and Ni5Y. The significance of these observations is discussed with respect to the current level of knowledge on the role of sulfur in the reactive-element effect. The ability of the reactive elements to getter sulfur is examined with respect to the thermodynamic stability of the oxysulfide species.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01046892
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    High-temperature oxidation of tantalum of different purity (1995)
    Springer
    Oxidation of metals 43 (1995), S. 509-526 
    Details
    ISSN: 1573-4889
    Keywords: oxidation ; kinetics ; tantalum ; oxide ; suboxide ; impurities ; diffusion
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract The kinetics, structural aspects, and phase morphologies were studied for tantalum oxidation in air from 600 to 1000°C for samples of different purity (99.15%, 99.76%, and 99.95% Ta). Regardless of purity, tantalum oxidation in the temperature range of 600–800°C as a rule is governed by a linear rate law. From 900 to 1000°C the initial-stage oxidation is governed by the parabolic rate law, which changes to the linear rate law with time. TGA, XRD, SEM, and AES methods were used. The, effect of purity on tantalum oxidation was shown to be determined by the mechanism of intermediate-oxide formation. They are TaO z (Ta2O) at 600–800°C and TaO at 900–1000°C. The final product of oxidation was β-Ta2O5.
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    URL: http://dx.doi.org/10.1007/BF01046896
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    The oxidation of Co−Nb alloys under low oxygen pressures at 600–800°C (1995)
    Springer
    Oxidation of metals 43 (1995), S. 527-542 
    Details
    ISSN: 1573-4889
    Keywords: Co−Nb alloys ; high temperature ; oxidation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract The oxidation of two Co−Nb alloys containing 15 and 30 wt.% Nb has been studied at 600–800° C in H2−CO2 mixtures providing an oxygen pressure of 10−24 atm at 600°C and 10−20 atm at 700 and 800°C, below the dissociation pressure of cobalt oxide. At 600 and 700°C both alloys showed only a region of internal oxidation composed, of a mixture of alpha cobalt and of niobium oxides (NbO2 and Nb2O5) and at 700°C also the double oxide CoNb2O6, which formed from the Nb-rich Co3Nb phase. No Nb-depleted layer formed in the alloy at the interface with the region of internal oxidation at these temperatures. Upon oxidation at 800°C a transition between internal and external oxidation of niobium was observed, especially for Co−30Nb. This corrosion mode is associated with the development of a single-phase, Nb-depleted region at the surface of the alloy. The corrosion mechanism of these alloys is examined with special reference to the effect of the low solubility of niobium in cobalt and to the relation between the microstructures of the alloys and of the scales.
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    URL: http://dx.doi.org/10.1007/BF01046897
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    The problem of sulfur in high-temperature corrosion (1995)
    Springer
    Oxidation of metals 44 (1995), S. 177-209 
    Details
    ISSN: 1573-4889
    Keywords: sulfidation ; oxidation ; common and refractory metals and alloys ; amorphous alloys
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract The role of defect and transport properties of transition metal sulfides on the kinetics and mechanism of high-temperature sulfide corrosion of metals and alloys is discussed. It has been shown, that due to the very high concentration of defects in common metal sulfides, not only pure metals but also conventional high-temperature alloys (chromia and alumina formers) undergo very rapid degradation in highly sulfidizing environments. Refractory metals, on the other hand, are highly resistant to sulfide corrosion, their sulfidation rates being comparable with the oxidation rate of chromium. Pioneering work of Douglasset al. has shown that alloying of common metals by niobium or molybdenum, and in particular combined alloying by molybdenumand aluminum, dramatically decreases the sulfidation rate. A novel Fe−30Mo−9Al alloy has been proved to be highly resistant to sulfide corrosion, its sulfidation rate being comparable with that of pure molybdenum. Even better resistance to highly-sulfidizing environments show new amorphous Al−Mo and Al−Mo−Si alloys, these materials also being simultaneously oxidation resistant. Thus, new prospects have been created for the development of a new generation of coating materials, resistant to multicomponent sulfidizing-oxidizing atmospheres, often encountered in many branches of modern technology.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01046727
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    Effect of short-circuiting on the oxidation kinetics of copper and its doped varieties in the temperature range of 523–1073 K (1996)
    Springer
    Oxidation of metals 46 (1996), S. 73-107 
    Details
    ISSN: 1573-4889
    Keywords: oxidation ; copper ; Li-doped copper ; Cr-doped copper ; short-circuiting ; Mott's parabola ; Wagner's parabola
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract The influence of shorting circuitry attachment between metal-oxide and oxideoxygen interfaces on the oxidation kinetics of copper, lithium-doped copper (Li: 400 ppm), and chromium-doped copper (Cr: 12 ppm) have been studied in dry air $$(P_{O_2 } = 21.27kPa)$$ in the temperature range of 523–1073 K. Oxide film or scale growth under short-circuiting as well as under normal oxidation conditions conforms to the parabolic rate law. The oxidation kinetics under short-circuiting resulted in decreased rates for Cu and Li-doped Cu up to a temperature of 773 K, while Cr-doped Cu exhibited an enhancement in rate compared to its normal oxidation in the same temperature range. However, above 873 K, all three systems under shorting circuitry attachment exhibited enhanced rates compared to their normal oxidation rates in conformity to the existing theoretical model. Use of additional resistances in series in the outer short-circuit Pt path have clearly established that below 773 K Mott's fieldinduced migration plays the most important role, while at elevated temperatures Wagner's electrochemical potential-gradient factor acts as the main driving force in the scale-growth process. The results have been interpreted on the basis of average defect concentration, the electrochemical potential gradient, electrical field gradient, and transport coefficient in the Cu2O layer.
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    URL: http://dx.doi.org/10.1007/BF01046885
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    Effect ofθ-alumina formation on the growth kinetics of alumina-forming superalloys (1996)
    Springer
    Oxidation of metals 46 (1996), S. 465-480 
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    ISSN: 1573-4889
    Keywords: ODS Alloy ; oxidation ; SIMS ; microstructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract Alumina-forming ODS superalloys are excellent oxidation-resistant materials. Their resistance relies upon the establishment of a stable, slow-growing, and adherent α-alumina. In the present investigation, these alloys exhibited unstable and relatively less adherent θ-alumina phase, which increased the oxidation rate in the transient stage and converted into α-alumina in the later part of the exposure. The oxide-growth process was found to depend upon various parameters such as temperature, time, and presence of an active elecment in the superalloy. Characterization carried out by XRD, SEM/EDAX, and AES on oxidized ODS and non-ODS alloys demonstrated a significant influence of the active element, Y, on the transformation of θ- to α-alumina. SIMS analysis of two-stage oxidation at 900°C for two different durations evidently showed that the change in the transport process is due to θ-to-α-alumina transformation. On the basis of these results, a new and consistent mechanism is proposed to explain the influence of θ-alumina and its transformation on growth kinetics and the effect of yttrium on the transformation leading to good scale adherence and oxidation resistance.
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    URL: http://dx.doi.org/10.1007/BF01048641
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    Effect of niobium additions on CO2-enhanced oxidation of titanium-aluminum intermetallic alloys (1997)
    Springer
    Oxidation of metals 48 (1997), S. 201-214 
    Details
    ISSN: 1573-4889
    Keywords: titanium-aluminum alloys ; niobium ; intermetallics ; oxidation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract In a recent study, CO2 has been reported to enhance the oxidation rate of binary titanium-aluminum alloys. The detrimental effect of CO2 was not, however, observed in a ternary alloy containing niobium. In this paper, possible explanations for these observations are examined. First, results from the literature regarding the effects of niobium in improving the resistance of titanium-aluminum alloys are briefly reviewed. Second, a thermodynamic analysis which offers a possible explanation for the beneficial effect of niobium in eliminating the CO2-enhanced oxidation of titanium-aluminum alloys is presented.
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    URL: http://dx.doi.org/10.1007/BF01670499
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    The air oxidation of two-phase Cu-Cr alloys at 700–900°C (1997)
    Springer
    Oxidation of metals 48 (1997), S. 357-380 
    Details
    ISSN: 1573-4889
    Keywords: chromium ; copper ; binary alloys ; two-phase alloys ; oxidation ; high temperatures
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract The oxidation in air of three two phase Cu-Cr alloys with nominal Cr contents of 25, 50, and 75 wt. % was studied at 700–900°C. The alloys corroded nearly parabolically, except at 900°C, when the corrosion rates decreased with time more rapidly than predicted by the parabolic rate law. The corrosion rate decreased for higher Cr contents in the alloy under constant temperature and generally increased with temperature for the same alloy composition. The scales were complex and consisted in most cases of an outermost copper oxide layer free from chromium and an inner layer composed of a matrix of copper oxide or of the double oxide Cu2Cr2O4, often containing particles of chromium metal surrounded by chromia and then by the double oxide. Metallic copper was also frequently mixed with chromia. Cr-rich regions tended to form continuous chromia layers at the base of the scale, especially at the highest temperature. No chromium depletion was observed in the alloy.
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    URL: http://dx.doi.org/10.1007/BF02153456
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    Role of kinetic effects on metal partition at the alloy-scale interface during the oxidation of alloys (1975)
    Springer
    Oxidation of metals 9 (1975), S. 215-223 
    Details
    ISSN: 1573-4889
    Keywords: cation diffusion ; oxidation ; metal partition
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract An alternative mass balance at the alloy-scale interface is proposed for the Wagner theory of binary alloy oxidation. A simple relation between the bulk composition of the alloy and the scale composition at the alloy-scale interface, ξ′, is derived in terms of the transport properties of the scale and the limit of application of the relation defined. There is good agreement between calculated and measured values of ξ′.
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    URL: http://dx.doi.org/10.1007/BF00613274
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    The oxidation behavior of an aligned Co-TaC eutectic alloy (1975)
    Springer
    Oxidation of metals 9 (1975), S. 225-257 
    Details
    ISSN: 1573-4889
    Keywords: oxidation ; eutectic alloys ; refractory metals
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract The oxidation behavior of the directionally aligned eutectic alloy, TaC-Co50B, has been examined between 600 and 1155°C. Parabolic oxidation behavior, isotropic in nature, is found to 800°C. Above 800°C, the oxidation behavior is no longer either parabolic or isotropic. The interaction between the Co matrix alloy and the TaC fibers adjacent to the oxidizing interface is reported as a function of temperature in oxidation.
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    URL: http://dx.doi.org/10.1007/BF00613275
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    Mechanical stresses developed in austenitic Fe-Cr-Ni alloys by oxidation in a CO2 atmosphere (1975)
    Springer
    Oxidation of metals 9 (1975), S. 259-274 
    Details
    ISSN: 1573-4889
    Keywords: stress ; oxidation ; austenitic steel ; CO2
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract The stresses developed during oxidation of Fe-Cr-Ni alloys in a CO 2 atmosphere at 600 and 700°C have been estimated by measuring the deflection of thin foil specimens oxidized on one side only. One side of the specimen was protected from oxidation by an Al-Au film which was oxidized prior to the deflection experiment. The character and magnitude of the stresses measured are explained by electron microscope and x-ray measurements. During the initial stage of oxidation, high stresses are formed due to epitaxial growth of the oxide. These stresses are high enough to plastically deform the alloy. As oxidation proceeds, the stress decreases and eventually reaches a “steady-state” value. During this stage, the alteration in composition and molecular volume of the oxide, the formation of carbides, and the growth of whiskers determine the stresses.
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    The high-temperature oxidation of Ni-20%Cr alloys containing various oxide dispersions (1975)
    Springer
    Oxidation of metals 9 (1975), S. 275-305 
    Details
    ISSN: 1573-4889
    Keywords: oxidation ; Ni-Cr alloys ; rare-earth oxide dispersion ; dispersion-strengthened alloys
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract The oxidation behavior of Ni-20%Cr alloys containing approximately 3 vol.% Y2O3, ThO2, and A12O3 as dispersed particles has been examined in the temperature range 900 to 1200° C in slowly flowing oxygen at 100 Torr. The results show that the oxidation behavior of the Y2O3-, ThO2-, Al2O3-, and Ce02-containing alloys is very similar and that some anomalies in the behavior of the ThO2-containing alloy might be explained by the slower rate of chromium diffusion in this coarse-grained alloy. Two Al2O3-containing alloys were studied. One with a relatively coarse dispersoid size behaved in a manner analogous to a dispersion-free Ni-30% Cr alloy at 1100°C. The other alloy contained a dispersion of fine Al2O3 particles and behaved exactly like the Y2O3-containing alloy at 1000 and 1100°C, but at 1200° C oxidized at a faster rate. It has been shown that the adherent scales on dispersion-containing alloys have a stabilized fine grain size, whereas the nonadherent scales on dispersion-free alloys undergo grain growth.
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    URL: http://dx.doi.org/10.1007/BF00613277
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    The effect of small amounts of silicon on the oxidation of high-purity Co-25 wt. % Cr at elevated temperatures (1975)
    Springer
    Oxidation of metals 9 (1975), S. 409-413 
    Details
    ISSN: 1573-4889
    Keywords: cobalt ; cobalt-chromium alloys ; silicon ; oxidation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract Some investigators have reported that Co-25 wt.% Cr oxidizes slowly at temperatures in the range 1000–1200°C forming a protective Cr2O3 scale; and this is the normal behavior of cobalt-base superalloys. Others have reported very rapid oxidation, forming a two-layer scale: an outer CoO layer and an inner mixture of Cr2O3 and CoCr2O4 particles in a CoO matrix. This investigation shows that the principal reason for this behavior is the purity of the material; it appears that the rapid mode of oxidation is the intrinsic behavior for high purity material. The most probable impurity to produce the slower mode is silicon, and it is shown that as little as 0.05 wt. % Si is sufficient to change the mode of oxidation provided sufficient oxygen is also present in the alloy: it seems probable therefore that a fine dispersion of SiO2 is responsible.
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    URL: http://dx.doi.org/10.1007/BF00611689
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    Study of the oxidation kinetics of vanadium carbide (1975)
    Springer
    Oxidation of metals 9 (1975), S. 415-425 
    Details
    ISSN: 1573-4889
    Keywords: vanadium carbide ; vanadium oxycarbide ; oxidation ; parabolic rate law ; cubic rate law ; chemisorption
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract The oxidation of an oxycarbide of vanadium, VO0.6C0.7, and of a vanadium carbide, VC0.98, was studied athermally up to temperatures of 800° C and isothermally between 400 and 580° C at oxygen pressures ranging from 10−2 to 1 atm. The oxycarbide followed the parabolic rate law below 450° C with V2O5 forming as the only reaction product. The activation energy was 49 kcal/mole. VC0.98 did not form an oxide in this temperature range, but rather dissolved oxygen, the activation energy being 26.6 kcal/mole. No oxygen pressure dependence on the kinetics was found for either sample in this temperature range. Both samples followed the cubic rate law during oxidation in the range of 500–580° C during which V2O5 formed. There was a P1/3 dependence and the activation energy was the same for both materials, 51 kcal/mole. The cubic rate law and the positive pressure dependency (rather than an anticipated negative dependency) were attributed to an electric field associated with oxygen ions chemisorbed on a thin layer of V2O5.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00611690
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    The high-temperature oxidation resistance of Co-Al alloys (1975)
    Springer
    Oxidation of metals 9 (1975), S. 427-440 
    Details
    ISSN: 1573-4889
    Keywords: cobalt ; cobalt-aluminum alloys ; oxidation ; thermal cycling
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract Most Ni and Co-base alloys used for high-temperature service rely on the production of a compact, stable Cr2O3 scale for their oxidation resistance. However, as operating temperatures have risen above 900–950° C, the loss of Cr2O3 as the volatile CrO3 has led to an inadequate life span of these alloys, particularly in rapidly flowing, turbulent gas streams. As a result of this, it has been necessary to examine the possibility of using Al2O3 as the protective scale. Al2O3 has a lower growth rate than Cr2O3, it is nonvolatile, and, unlike Cr-containing systems, it is less likely to form compound oxides such as spinels. In this study, the amount of Al which must be present in the Co-Al system to form a continuous layer of Al2O3 in the temperature range 800–1000° C has been determined. The quantity was found to rise from about 7–10 wt. % at 800° C to 10–13 wt. % at 900° C and 13 wt. % at 1000° C. Notice has also been taken of the abilities of the alumina-forming alloys to re-form a protective oxide in the event of spalling, blistering, or any other disruptions of the scale, and some “cyclic-oxidation” checks have been conducted on the Co13Al alloy at 900 and 1000° C.
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    URL: http://dx.doi.org/10.1007/BF00611691
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  • 82
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    Effect of oxide grain structure on the high-temperature oxidation of Cr (1975)
    Springer
    Oxidation of metals 9 (1975), S. 459-472 
    Details
    ISSN: 1573-4889
    Keywords: Cr ; oxidation ; kinetics ; Cr2O3 grain size ; short-circuit diffusion ; surface ; preparation ; Fe-Cr
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract Cr was oxidized in 1 aim O2 at 980, 1090, and 1200°C. ElectropolishedCr and some orientations of etched Cr oxidize rapidly and develop compressive stress in the growing Cr2O3; other orientations oxidize slowly, apparently free of stress. SEM examination of fracture sections shows that the thick oxide is polycrystalline whereas the thin oxide on etched Cr is monocrystalline. It is deduced that the monocrystalline oxide grows by lattice diffusion of cations outward, and the polycrystalline layer by the two-way transport of cation diffusion outward and anion diffusion inward along oxide grain boundaries. The consequent formation of oxide within the body of the polycrystalline layer generates compressive stress and leads to wrinkling by plastic deformation. The activation energy for oxidation of Cr by cation lattice transport is 58 kcal/mole. Polycrystalline Cr2O3 forms on Fe-26Cr alloy, whether electropolished or etched; oxidation is accordingly rapid and accompanied by compressive stress.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00611694
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  • 83
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    The oxidation and hot corrosion behavior of tungsten-fiber reinforced composites (1975)
    Springer
    Oxidation of metals 9 (1975), S. 45-67 
    Details
    ISSN: 1573-4889
    Keywords: oxidation ; hot corrosion ; nickel alloys ; composites
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract The oxidation and hot corrosion behavior of a tungsten-fiber, reinforced Ni~ 20Cr alloy has been examined under the following exposure conditions: (a) pure oxygen at 1 atm pressure; (b) sulfidation in H2–10 %H2S; (c) presulfidation in H2–10 %H2S followed by oxidation in oxygen; and (d) oxidation in 1 atm oxygen after precoating with approximately 1 mg/cm2 of Na2SO4. Rapid oxidation of the tungsten fibers causes considerable distortion of the matrix and catastrophic degradation of the matrix follows. Inter diffusion between the matrix and the fibers is also important. During sulfidation, only the matrix forms sulfides, the fibers remaining unaffected. Consequently, presulfidation, although having a dramatic effect on the oxidation of the matrix does not have a damaging effect on the fibres. Equally, the presence of sodium sulfate is not critical, although severe oxidation of the exposed tungsten fibers is still observed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00613494
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  • 84
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    Kinetics of the oxidation of ilmenite (1975)
    Springer
    Oxidation of metals 9 (1975), S. 99-116 
    Details
    ISSN: 1573-4889
    Keywords: oxidation ; kinetics ; ilmenite ; rutile ; pseudobrookite
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract The oxidation of ilmenite (FeTiO3) in air and dry oxygen was investigated over the temperature interval 600 to 970°C. Dense platelets of ilmenite crystals as well as powder samples of ilmenite were oxidized. The weight data were recorded employing a thermobalance. The oxidation kinetics of ilmenite platelets were parabolic except for the initial stages during which logarithmic kinetics were observed. For powder samples the logarithmic rate law was followed primarily. The logarithmic rate law was attributed to free penetration of oxygen through cracks and short-circuit paths. The activation energies associated with the logarithmic rate law were nearly one-half of those obtained from parabolic oxidation. The growth morphology of the products of oxidation of ilmenite was observed with a scanning electron microscope. The effect of growth morphology on the kinetics is discussed, and a probable reaction mechanism is suggested for the oxidation of ilmenite.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00613496
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  • 85
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    The oxidation and decarburizing of Fe-C alloys in air and the influence of relative humidity (1975)
    Springer
    Oxidation of metals 9 (1975), S. 69-97 
    Details
    ISSN: 1573-4889
    Keywords: oxidation ; decarburization ; Fe-C alloys ; effect of humidity ; effect of microstructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract Isothermal oxidation treatments were carried out on an Fe-C alloy (0.4 % C): (a) in almost dry air around A1, and also with an Fe-C alloy (0.5% C) and IRSID pure iron; (b) in dry air ( $${\text{P}}_{H_2 O} \simeq 10^{ - 5} $$ nm Hg); (c) in almost dry air(1–2% water vapor) at 700° C; and (d) in moist air (31% water vapor). Theresults are as follows: The rate of oxidation at a temperature below A1depends chiefly on alloy structure, i.e., on thermal history of the sample.The water vapor content of the air strongly influences the scale adherenceas well as the rate of oxidation of the Fe-C alloys below A1, but has virtuallyno effect on the rate of oxidation of pure iron. Under the same conditions, avery light decarburization of metal occurs in air, whereas no decarburizationoccurred in air with 13% water vapor.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00613495
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  • 86
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    Yttrium Acetate-Derived Particle Coatings for Mitigating Oxidation and Corrosion of Inconel 625 (1998)
    Springer
    Journal of sol gel science and technology 12 (1998), S. 35-48 
    Details
    ISSN: 1573-4846
    Keywords: yttrium acetate precursor ; particle coating ; oxidation ; corrosion ; Inconel
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract “Sol paint” that yields yttrium-based compounds was prepared by mixing four chemical ingredients, yttrium acetate tetrahydrate precursor, diethanolamine, isopropyl alcohol, and hydrochloric acid, and then applied as oxidation/corrosion resistant coatings for Inconel 625 substrates. Annealing the coatings at 500°C developed a coalescent microstructure of coarse particles consisting of amorphous yttrium carbonate as the major component and crystalline yttrium oxide (Y2O3) as the minor one. At 700°C, the yttrium carbonate was transformed into Y2O3 by decarbonation. Increasing the annealing temperature to 900°C led to the formation of the YCrO3 phase yielded by interaction between Y2O3 and the Cr2O3 which had arisen from the oxidation of the underlying Inconel; the YCrO3 phase created a particle coating with a densified microstructure. There were two key factors in mitigating the degree of oxidation of Inconel at 900°C in air: (1) an uptake of oxygen by Y2O3 in the coatings, and (2) a densified coating layer that suppresses the diffusion and permeation of oxygen through it. Furthermore, inhibiting the rate of NaCl-caused corrosion was not only due to the excellent coverage of particle coatings over the entire surfaces of the substrates, but also may be associated with a good adherence of the coatings to the substrates.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1008653026137
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  • 87
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    Insights into the Oxidation Chemistry of SiOC Ceramics Derived from Silsesquioxanes (1999)
    Springer
    Journal of sol gel science and technology 14 (1999), S. 49-68 
    Details
    ISSN: 1573-4846
    Keywords: silicon oxycarbide ; oxidation ; silsesquioxane ; preceramic
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract We have undertaken a systematic study of the oxidation chemistry for a range of SiOC ceramics derived from silsesquioxane polymeric precursors. This study examines the oxidation for 500 hours at 600, 800, 1000 and 1200°C for four SiOC powders. The material changes upon oxidation were characterized qualitatively by color change and optical microscopy and quantitatively by weight and composition change. In this study we employ a very easy method that uses the weight change upon oxidation and a carbon analysis after oxidation to arrive at the composition of the oxidized SiOC. Combined these qualitative and quantitative techniques have shown that on oxidation at 800 and 600°C the SiOC composition is more rapidly changed to that of silica than oxidation over the same time frame at 1000 or 1200°C. The data indicates that this difference is due to the relative rates of oxidation of the excess carbon versus the Si—C bonds in the SiOC. At lower temperatures initially the carbon oxidation predominates which leads to higher porosity throughout the material and an increase in the surface area with eventually ‘complete’ oxidation to silica. At higher temperatures the Si—C bond oxidation rate is comparable to the rate of oxidation of carbon. This allows a silica-like surface to build up on the SiOC, which slows all subsequent reactions due to the necessity to diffuse O2 in and COx out of the bulk. Under these oxidation conditions materials that originally contain high amounts of excess carbon are more quickly oxidized to silica than those that contain minimal amounts of excess carbon, as confirmed by elemental analysis and optical microscopy. Regardless of the time or temperature of the oxidation conditions no materials were found to be completely stable to oxidation. SiOC materials with low levels of excess carbon showed the best resistance to change upon oxidation.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1008723813991
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  • 88
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    Tailoring Silicon Oxycarbide Glasses for Oxidative Stability (1999)
    Springer
    Journal of sol gel science and technology 14 (1999), S. 75-86 
    Details
    ISSN: 1573-4846
    Keywords: silicon oxycarbide ; BlackglasTM ; ceramic matrix composites ; 29Si NMR ; oxidation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract BlackglasTM polysiloxane systems produce silicon oxycarbide glasses by pyrolysis in inert atmosphere. The silicon oxycarbides evidence oxidative degradation that limits their lifetime as composite matrices. The present study characterizes bonding rearrangements in the oxycarbide network accompanying increases in pyrolysis temperature. It also addresses the changes in susceptibility to oxidation due to variations in the distribution of Si bonded species obtained under different processing conditions. The study is carried out using 29Si nuclear magnetic resonance (NMR) spectroscopy and a design of experiments approach to model the oxidation behavior. The NMR results are compared with those obtained by thermogravimetric analysis (TGA). Samples pyrolyzed under inert conditions are compared to those pyrolyzed in reactive ammonia environments.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1008727914900
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  • 89
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    TEM Observation of the Zrc/Zro2 Interface Formed by Oxidation of Zrc Single Crystals (1998)
    Springer
    Journal of materials synthesis and processing 6 (1998), S. 191-195 
    Details
    ISSN: 1573-4870
    Keywords: Transmission electron microscopy observation ; interfacial microstructure ; oxidation ; ZrC ; cubic ZrO2 ; amorphous carbon film
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract Microstructure at the interface of ZrC and ZrO2 formed by oxidation of a single crystal of ZrC with 100 faces at 600°C at an oxygen pressure of 2 kPa was observed by high-resolution transmission electron microscopy and scanning electron microscopy. The ZrO2 scale was shown to consist of two subscales, zones 1 and 2. The interfacial area in zone 1 was composed of regular lattice fringes corresponding to the 111, 200, and 220 lattices of cubic ZrO2 (c-ZrO2) crystallites 2 to 10 nm in size and an amorphous phase. The growth of crystallites occurred in zone 2, which visualized the interface of zones 1 and 2. Black thin films reminiscent of zone 1 were successfully separated, which were composed of amorphous carbon in which c-ZrO2 particles 2 to 20 nm in size were included.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1022673620322
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  • 90
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    Modification of the oxidation behavior of high-purity austenitic Fe-14Cr-14Ni by the addition of silicon (1976)
    Springer
    Oxidation of metals 10 (1976), S. 1-22 
    Details
    ISSN: 1573-4889
    Keywords: oxidation ; film spalling ; fayalite ; internal oxidation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract The oxidation behavior of Fe-14Cr-14Ni (wt.%) and of the same alloy with additions of 1 and 4% silicon was studied in air over the range of 900-1100° C. The presence of silicon completely changed the nature of the oxide scale formed during oxidation. The base alloy (no silicon) formed a thick outer scale of all three iron oxides and an internally oxidized zone of (Fe,Cr,Ni) spinels. The alloy containing 4% silicon formed an outer layer of Cr2O3 and an inner layer of either (or possibly both) SiO2 and Fe2SiO4. The formation of the iron oxides was completely suppressed. The oxidation rate of the 4% silicon alloy was about 200 times less than that of the base alloy, whereas the 1% silicon alloy exhibited a rate intermediate to the other two alloys. The actual ratio of the oxidation rates may be less than 200 due to possible weight losses by the oxidation of Cr2O3 to the gaseous phase CrO3. The lower oxidation rate of the 4% silicon alloy was attributed to the suppression of iron-oxide formation and the presence of Cr2O3, which is a much more protective scale.
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    URL: http://dx.doi.org/10.1007/BF00611695
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  • 91
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    Kinetics of high-temperature oxidation of boron carbide in oxygen (1976)
    Springer
    Oxidation of metals 10 (1976), S. 85-95 
    Details
    ISSN: 1573-4889
    Keywords: boron carbide ; oxidation ; kinetics ; chromatography method
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract Thermogravimetry and gas-adsorption chromatography were used to study the kinetics of formation of solid and gaseous products during the hightemperature oxidation of compact boron carbide in oxygen at 740 Torr. Oxidation resistance was observed at temperatures up to 1200°C. The main oxidation products were B2O3 and CO2. Oxidation was paralinear; the carbon consumption exceeded the consumption of boron as compared to the ratio of these elements in the compound B4C. This difference resulted in carbon depletion of the carbide layer in the substrate near the scale〉.
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    URL: http://dx.doi.org/10.1007/BF00614238
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  • 92
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    High-temperature oxidation of SiC in a glow-discharge oxygen plasma (1976)
    Springer
    Oxidation of metals 10 (1976), S. 97-103 
    Details
    ISSN: 1573-4889
    Keywords: silicon carbide ; oxidation ; molecular oxygen ; glow-discharge oxygen plasma ; kinetics
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract The oxidation kinetics and structure of the oxide scales formed on high-density SiC were studied in molecular oxygen at 740 Torr and in a glow-discharge oxygen plasma at 0.1 Torr at temperatures of 1000, 1100, and 1200°C. The monatomic oxygen formed by the glow discharge markedly increased the reaction rate and the vaporization of some of the oxidation products. The marked differences in kinetics suggest that the rate-controlling step during oxidation in molecular oxygen is the dissociation of adsorbed diatomic oxygen to the monatomic species. Films formed in molecular oxygen were mostly amorphous SiO2 with small inclusions of SiC and graphite, whereas films formed in dissociated oxygen were primarily amorphous SiO2 containing SiO, S2O3, and the coesite form of SiO2.
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    URL: http://dx.doi.org/10.1007/BF00614239
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    Theoretical study of heterogeneous reaction kinetics: A comparison between microcalorimetric and thermogravimetric curves (1976)
    Springer
    Oxidation of metals 10 (1976), S. 105-111 
    Details
    ISSN: 1573-4889
    Keywords: kinetics ; oxidation ; microcalorimetry ; thermogravimetry
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract In the kinetic theories of Bodenstein or Semenov the expression for the rate of a chemical reaction with several elementary stages can be expressed by different physical parameters. If two experimental methods are used, one method of necessity being microcalorimetry to measure the thermal flux produced by the reaction, it is possible to distinguish a pure kinetics case from a mixed one. The two-method technique has been verified by a study of the oxidation of niobium.
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    URL: http://dx.doi.org/10.1007/BF00614240
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  • 94
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    Development, growth, and adhesion of Al2O3 on platinum-aluminum alloys (1976)
    Springer
    Oxidation of metals 10 (1976), S. 189-223 
    Details
    ISSN: 1573-4889
    Keywords: oxidation ; platinum ; platinum-aluminum alloys ; alumina (Al2O3) ; oxide-scale adhesion
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract The development, growth, and adhesion of α-Al2O3 scales on platinum-aluminum alloys containing between 0.5 and 6 wt.% aluminum have been studied at temperatures in the interval between 1000 and 1450° C. The morphologies and microstructures of the α-Al2O3 scales were found to be influenced by the temperature, oxygen pressure, and the microstructures of the alloys. The oxidation rates of the alloys appeared to be controlled by transport of oxygen along grain boundaries in the α-Al2O3 scales. The α-Al2O3 scales adhered to the platinum-aluminum substrates even after extensive periods of cyclic oxidation. The good adhesion of the α-Al2O3 may result from mechanical keying of the oxide to the alloys due to the development of irregular oxide-alloy interfaces.
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    URL: http://dx.doi.org/10.1007/BF00612159
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  • 95
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    Oxidation of high-chromium Ni-Cr alloys (1979)
    Springer
    Oxidation of metals 13 (1979), S. 119-158 
    Details
    ISSN: 1573-4889
    Keywords: nickel-chromium alloys ; oxidation ; high temperature ; kinetics ; mechanisms
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract The oxidation of binary Ni-Cr alloys containing 44 and 50 wt. % Cr has been studied over a range of oxygen partial pressures at temperatures between 800 and 1100°C. The effects of cold work, surface preparation, and distribution of the Cr-rich second phase have been studied. The oxidation behavior is complex and cannot be described by a single model. The oxide grows by short-circuit diffusion as well as bulk transport through Cr 2 O 3 scales. The scale-growth mechanism includes extensive metal-oxide separation requiring Cr vapor transport to the scale, compressive stresses within the oxide which result in scale bulging and cracking, and the formation of a second oxide layer which results in voids being incorporated into the scale. Any factor which reduces the oxide grain size, such as cold work, finer distribution of the Cr-rich α phase or reduced oxygen pressure, results in an increased oxidation rate of binary alloys because of an increased number of grain-boundary short-circuit diffusion paths.
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    URL: http://dx.doi.org/10.1007/BF00611976
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    High-temperature oxidation of copper-manganese alloys (1979)
    Springer
    Oxidation of metals 13 (1979), S. 181-195 
    Details
    ISSN: 1573-4889
    Keywords: copper-manganese alloys ; oxidation ; scale composition
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract The oxidation behavior of copper-manganese alloys (2–35 wt. % Mn) in pure oxygen at 760 Torr was investigated at 100° intervals between 550 and 850°C. Gravimetric measurements of the oxidation kinetics have been combined with microstructural studies of the reacted samples in order to evaluate the reaction mechanisms. The scales formed on Cu-2Mn, Cu-5Mn, Cu-10Mn are always composed of three different layers; in any case manganese is present only in the inner layer. The scales formed on Cu-20Mn and Cu-35Mn are composed of two layers, both containing manganese, with a more Cu-rich outer layer. In all the samples internal oxidation in combination with external scale formation is observed.
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    URL: http://dx.doi.org/10.1007/BF00611978
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    The effect of cerium on the oxidation of Ni-50Cr alloys (1979)
    Springer
    Oxidation of metals 13 (1979), S. 159-180 
    Details
    ISSN: 1573-4889
    Keywords: nickel-chromium alloys ; oxidation ; high temperature ; cerium
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract The oxidation behavior of Ni-50Cr alloys with minor cerium additions was studied between 800 and 1100° Cin oxygen, air, and oxygen at reduced partial pressures. Optical and scanning electron metallography, X-ray diffraction, and electron-probe microanalysis techniques were used to characterize the changes in scale and substrate morphology and to identify the oxidation products. Platinum markers were used to determine the direction of ionic transport. The effects of cold work, initial alloy phase distribution, and cyclic oxidation were also studied. The Cr 2 O 3 scales on the cerium-containing alloys grew while being largely separated from the metal substrate. Oxidation rate, oxide grain growth, and the tendency of scales to spall on cooling were reduced substantially with increasing alloy cerium content. The first two effects are suggested to result from the interaction of cerium ions and cerium oxide particles with oxide grain boundaries in reducing grain-boundary diffusion and oxide-boundary mobility. The third is suggested to result from the thinner, finer-grained scales formed on the Ce-containing alloys.
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    URL: http://dx.doi.org/10.1007/BF00611977
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    Surface oxidation of nickel metal as studied by X-Ray photoelectron spectroscopy (1979)
    Springer
    Oxidation of metals 13 (1979), S. 223-236 
    Details
    ISSN: 1573-4889
    Keywords: nickel ; oxidation ; surface reactions ; X-ray photoelectron spectroscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract X-ray photoelectron spectroscopy has been used to study the oxidation of polycrystalline nickel metal. The results indicate that the oxidation process takes place in three stages; associative adsorption of molecular oxygen, followed by the combination of oxygen atoms with surface nickel atoms and, ultimately, the formation of bulk oxide. At room temperature only the first two stages can be detected. For exposures below 1 L the O 1s photoelectron spectrum is considered to be characteristic of an associatively adsorbed oxygen species, but for exposures above this value evidence for the formation of a monolayer of “NiO” is suggested by the development of an O 1s peak at 529.9 eV. Incorporation of oxygen into the nickel lattice is observed at temperatures 〉500°K. The activation energy for this place-exchange process was estimated at 1.80±0.06 eV.
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    URL: http://dx.doi.org/10.1007/BF00603667
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    Oxidation of Fe-C alloys at 700°C (1979)
    Springer
    Oxidation of metals 13 (1979), S. 255-272 
    Details
    ISSN: 1573-4889
    Keywords: oxidation ; Fe-C ; graphite deposition ; nonadherent oxide ; kinetics
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract The oxidation of Fe-C alloys containing 0.5 and 1.0% C was studied in 1 atm O2 at 700° C. The oxidation rate is considerably slower than for pure Fe. The oxide scale formed is detached, multilayered, and overoxidized, containing little or no FeO. A thin film of graphite was identified at the metal-oxide interface by electron diffraction. It is proposed that the slow oxidation and abnormal scale are caused by a residue of graphite left at the metal surface from the oxidation of Fe3C. This inhibition of the oxidation of Fe by carbon at 700°C is in contrast to the stimulation observed at 500°C.
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    URL: http://dx.doi.org/10.1007/BF00603670
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  • 100
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    The oxidation of Fe-Cr surface and bulk alloys at 300°C (1979)
    Springer
    Oxidation of metals 13 (1979), S. 283-298 
    Details
    ISSN: 1573-4889
    Keywords: oxidation ; surface alloys ; Fe-Cr alloys ; iron ; kinetics
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract The oxidation behavior of several surface and bulk Fe-Cr alloys and iron at 300°C and 4×10−6 Torr oxygen was studied. The surface alloys were fabricated by implantation of 25 keV Cr ions into the outermost 300Å of polycrystalline iron samples. The oxide thickness as a function of oxygen exposure was obtained using proton-excited X-ray analysis, and composition profiles of oxide films were obtained using Auger electron spectroscopy and ion sputtering. The addition of Cr to Fe by surface and bulk alloying caused the oxidation rate to decrease and changed the oxidation kinetics from parabolic (for Fe) to logarithmic (for Cr concentrations ≥4.7at.%). Interpretation of the data in terms of simple oxidation theories indicates that the Cr additions may reduce the oxidation rate by altering the electronic properties of the metal-oxide interface.
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    URL: http://dx.doi.org/10.1007/BF00603672
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