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  • 1
    Electronic Resource
    Electronic Resource
    Impurity-induced degradation at zirconia/sapphire interfaces (1997)
    Springer
    Journal of materials science 32 (1997), S. 2903-2910 
    Details
    ISSN: 1573-4803
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract Sapphire fibre surface damage caused by a polycrystalline zirconia coating has been analysed using scanning electron microscopy (SEM) and electron probe microanalysis (EPMA). “Pitting” of the sapphire surface was partially attributed to formation of a transient liquid phase (interphase) capable of local dissolution of alumina at zirconia grain contacts. Chemical etching was used to verify that the interphase material was silicate-based and resided at triple points between zirconia grains and the fibre surface. An additional crystalline calcium hexaluminate phase (hibonite) was found on some fibres. Origin of these impurities and resulting consequences of their presence are rationalized in view of observed surface modification.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1018680602276
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  • 2
    Electronic Resource
    Electronic Resource
    Orientation of polybutadiene chains in a thermoplastic elastomer (1996)
    Springer
    Colloid & polymer science 274 (1996), S. 723-731 
    Details
    ISSN: 1435-1536
    Keywords: Orientation ; deformation ; thermoplastic elastomer
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract The orientation of polybutadiene chains in thermoplastic elastomers based on hydrogen bonding complexes is investigated under uniaxial deformation by two-dimensional small-angle neutron scattering (SANS), deuteron magnetic resonance spectroscopy (2H-NMR), optical birefringence and infrared dichroism spectroscopy (FTIR-D). While SANS probes orientation on the length scale of the radius of gyration,2H-NMR, birefringence and FTIR-D monitor orientation on a segmental scale. The deformation of the elastomer chains appears to be affine on the different length scales.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00654667
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  • 3
    Electronic Resource
    Electronic Resource
    Test methodology for the thermal shock characterization of ceramics (1998)
    Springer
    Journal of materials science 33 (1998), S. 5427-5432 
    Details
    ISSN: 1573-4803
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract An experimental methodology is proposed to evaluate the thermal shock resistance of ceramics. A technique based on infrared heating has been developed to perform systematic and well controlled thermal shock experiments. This novel technique was used to evaluate the resistance of yttria-stabilized zirconia–alumina foams to thermal loads. Foams of varying cell sizes were subjected to thermal shock and the damage was evaluated using retained strength and non-destructive elastic modulus measurements. The transient thermal gradients and the resulting thermoelastic stresses in the foams were predicted using finite element analysis and the extent of damage was correlated to the maximum thermal strains generated in foams.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1004410719754
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  • 4
    Electronic Resource
    Electronic Resource
    Interfacial stress state present in a “thin-slice” fibre push-out test (1992)
    Springer
    Journal of materials science 27 (1992), S. 3821-3826 
    Details
    ISSN: 1573-4803
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract An analysis of the stress distributions along the fibre-matrix interface in a “thin-slice” fibre push-out test is presented for selected test geometries. For the small specimen thicknesses often required to displace large-diameter fibres with high interfacial shear strengths, finite element analysis indicates that large bending stresses may be present. The magnitude of these stresses and their spatial distribution can be very sensitive to the test configuration. For certain test geometries, the specimen configuration itself may alter the interfacial failure process from one which initiates due to a maximum in shear stress near the top surface adjacent to the indentor, to one which involves mixed mode crack growth up from the bottom surface and/or yielding within the matrix near the interface.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00545464
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  • 5
    Electronic Resource
    Electronic Resource
    Influence of interfacial microcracks on the elastic properties of composites (1996)
    Springer
    Journal of materials science 31 (1996), S. 3179-3184 
    Details
    ISSN: 1573-4803
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract A model is established to quantify the influence of interfacial microcracks on the elastic properties of a particulate composite using a combination of theoretical and finite element analysis. A unique way to construct physical models which could accommodate both crack size and crack density is proposed. Based on energy principles, the influence of a dilute concentration of interfacial microcracks is first studied. The case of a finite concentration of microcracks is solved subsequently by combining the dilute concentration solutions and the differential scheme. Both cases agreed well with existing composite theories for the limiting condition of complete decohesion. The final model predicts the effective elastic properties as functions of both crack size and microcrack density.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00354665
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  • 6
    Electronic Resource
    Electronic Resource
    The effect of grain-boundary devitrification on the wear of glass-bonded alumina ceramics (1994)
    Springer
    Journal of materials science 29 (1994), S. 3665-3672 
    Details
    ISSN: 1573-4803
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract The steady-state wear behaviour of a 94 wt% alumina was investigated in the as-fired condition and after a post-sintering heat treatment. The post-sintering heat treatment yielded devitrification of the 6 wt% calcia-magnesia-alumino-silicate (CaO · MgO · Al2O3 · SiO2) glass grain-boundary phase. In addition, the effect of surface finishing on the wear behaviour of as-fired and heat-treated samples was studied. Steady-state wear rates were determined using a single-pin-on-disc tribometer. The results indicated that heat treated, unfinished samples exhibit a higher steady-state wear rate than as-fired, unfinished samples. The differences observed may arise in response to one or more of the following mechanisms: (i) creation of intergranular thermoelastic stresses due to thermal-expansion mismatch among intergranular species, (ii) elimination of the lubricative glass phase in devitrified specimens, and (iii) elimination of the advantageous effects of viscoplastic deformation of the intergranular glassy phase on stress relaxation. Surface finishing further increased the steady-state wear rate of the heat-treated samples only, and it correlated with an increase in subsurface microcracking and grain pull-out. A lubricative glass film was found to persist on all sample wear tracks, suggesting that the differences in wear behaviour are dominated by intergranular fracture and grain pull-out.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00357333
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  • 7
    Electronic Resource
    Electronic Resource
    Synthesis of castable sodium zirconium phosphate monoliths employing reactions between zirconyl nitrate hydrate and condensed phosphates (1999)
    Springer
    Journal of materials science 34 (1999), S. 1809-1813 
    Details
    ISSN: 1573-4803
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract Reactions between zirconyl nitrate hydrate and condensed phosphates can be used to produce castable low CTE sodium zirconium phosphate (NZP) monoliths. Reaction between sodium nitrate, zirconyl nitrate hydrate and condensed phosphoric acid at room temperature (alkali nitrate method) produces monoliths having a heterogeneous microstructure, which are multiphasic in appearance. Except for the presence of crystalline sodium nitrate, they are X-ray amorphous. Differential thermal analysis revealed two distinct exothermic crystallization events when these materials are heated. The first event, with an onset temperature of 650°C, is the result of NZP and ZrO2crystallization. The second is the result of ZrP2O7 crystallization. Reaction between zirconyl nitrate hydrate and condensed sodium phosphate (condensed alkali phosphate method) results in a more homogeneous microstructure in which crystalline zirconium hydrogen phosphate hydrate and sodium nitrate are present. Two exothermic peaks, with onset temperatures of approximately 570 and 860°C, are observed. The first exotherm is the result of NZP, ZrO2 and ZrP2O7 crystallization; the second exotherm is the result of a further NZP formation. After heating materials made by these two methods at 940°C for 24 h, the condensed-alkali-phosphate-method-derived material converted to phase-pure NZP, while the alkali-nitrate-method-derived material contained ZrP2O7. The differences in phase evolution between the materials prepared by these two methods are attributable to the differences in chemical and microstructural homogeneity that result from the reactants used.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1004563309860
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  • 8
    Electronic Resource
    Electronic Resource
    Beiträge zur Chemie des Phosphors. 134. Über die Triphosphane H(t-BuP)3H, Li(t-BuP)3Li und Me3Si(t-BuP)3SiMe3 (1984)
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 509 (1984), S. 38-52 
    Details
    ISSN: 0044-2313
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Contributions to the Chemistry of Phosphorus. 134. On the Triphosphanes H(t-BuP)3H' Li(t-BuP)3Li, and Me3Si(t-BuP)3SiMe3The reaction of 1,3-diiodo-1,2,3-tri-tert-butyltriphosphane, I(t-BuP)3I, with lithium aluminium hydride leads to 1,2,3-tri-tert-butyltriphosphane, H(t-BuP)3H (1). 1 reacts with n-butyllithium to 1,3-dilithium-1,2,3-tri-tert-butyltriphosphide, Li(t-BuP)3Li (2), which reacts further with trimethylchlorosilane yielding 1,3-bis(trimethylsilyl)-1,2,3-tri-tert-butyltriphosphane, Me3Si(t-BuP)3SiMe3 (3). The triphosphanes 1, 2 and 3 could be isolated in a pure state. In solution 1 forms the threo, threo and the threo,erythro configurated diastereomers 1a and 1b in a ratio of about 2:1. 3 predominantly exists in form of the threo,erythro configurated diastereomer 3b by steric reasons.
    Notes: Die Umsetzung von 1,3-Diiod-1,2,3-tri-tert-butyltriphosphan, I(t-BuP)3I, mit Lithiumaluminiumhydrid führt zu 1,2,3-Tri-tert-butyltriphosphan, H(t-BuP)3H (1). 1 reagiert mit n-Butyllithium zu 1,3-Dilithium-1,2,3-tri-tert-butyltriphosphid, Li(t-BuP)3Li (2), das mit Trimethylchlorsilan weiter zu 1,3-Bis(trimethylsilyl)-1,2,3-tri-tert-butyltriphosphan, Me3Si(t-BuP)3SiMe3 (3), umgesetzt werden kann. Die Triphosphane 1, 2 und 3 konnten in reiner Form isoliert werden. In Lösung bildet 1 die threo, threo- und threo,erythro-konfigurierten Diastereomere 1 a und 1 b im Verhältnis von etwa 2:1. 3 liegt aus sterischen Gründen hauptsächlich in Form des threo, erythro-konfigurierten Diastereomers 3 b vor.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/zaac.19845090204
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  • 9
    Electronic Resource
    Electronic Resource
    Beiträge zur Chemie des Phosphors. 136 [1]. 31P-Kernresonanzspektren und Struktur der 1,3-Dihalogen-1,2,3-tri-tert-butyltriphosphane X(t-BuP)3X, X = Cl, Br, I (1984)
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 509 (1984), S. 53-60 
    Details
    ISSN: 0044-2313
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Contributions to the Chemistry of Phosphorus. 136. 31P-N.M.R. Spectra and Structure of 1,3-Dihalogen-1,2,3-tri-tert-butyltriphosphanes X(t-BuP)3X, X = Cl, Br, IThe 1,3-dihalogen-1,2,3-tri-tert-butyltriphosphanes (t-BuP)3Cl2 (1), (t-BuP)3Br2 (2), and (t-BuP)3I2 (3), which are formed in the halogenating ring cleavage of tri-tert-butyl-cyclotriphosphane, (t-BuP)3, by halogens or halogen compounds, favour the erythro, threo configuration by steric reasons. However, the erythro, erythro configurated diastereomer, whose stability depends on the size of the halogen substituents and on the rate of inversion at the phosphorus atoms, is formed initially. The reaction of the erythro, erythro and erythro, threo configurated diastereomers of 1-3 with lithium aluminium hydride leads stereospecifically to the threo, threo and threo, erythro configurated diastereomers of 1,2,3-tri-tert-butyltriphosphane, H2(t-BuP)3 (4), respectively.
    Notes: Die 1,3-Dihalogen-1,2,3-tri-tert-butyltriphosphane (t-BuP)3Cl2 (1), (t-BuP)3Br2 (2) und (t-BuP)3I2 (3), die bei der halogenierenden Ringspaltung von Tri-tert-butyl-cyclotriphosphan, (t-BuP)3, mit Halogenen oder Halogenverbindungen gebildet werden, bevorzugen aus sterischen Gründen die erythro, threo-Konfiguration. Zunächst entsteht jedoch das erythro, erythro-konfigurierte Diastereomer, dessen Stabilität von der Größe der Halogensubstituenten und der Inversionsgeschwindigkeit der Phosphoratome abhängt. Die Reaktion der erythro, erythro- bzw. erythro, threo-konfigurierten Diastereomere von 1-3 mit Lithiumaluminiumhydrid führt stereoselektiv zu den threo, threo- bzw. threo, erythro-konfigurierten Diastereomeren von 1,2,3-Tri-tert-butyltriphosphan, H2(t-BuP)3 (4).
    Additional Material: 1 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/zaac.19845090205
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  • 10
    Electronic Resource
    Electronic Resource
    Beiträge zur Chemie des Phosphors. 111. 1,2-Dichlor-1,2-di-tert-butyldiphosphan (1982)
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 489 (1982), S. 11-15 
    Details
    ISSN: 0044-2313
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Contributions to the Chemistry of Phosphorus. 111. 1,2-Dichloro-1,2-di-tert-butyl-diphosphaneThe reaction of tri-tert-butyl-cyclotriphosphane, (t-BuP)3, with phosphorus(V) chloride (molar ratio 1:2) leads to the title compound Cl(t-Bu)P—P(t-Bu)Cl (1), which is remarkably stable against disproportionation reactions. As the first 1,2-dichloro-1,2-diorganyldiphosphane, 1 has been isolated in a pure state and was thoroughly characterized. At room temperature, 1 exists in a mixture of the d,l and meso form (about 20:80). The mutual repulsion of the negative polarized Cl atoms and their preferred gauche arrangement to the free electron pairs of neighboured P atoms leads to a gauche-conformation of the lone electron pairs in the d,l- and to a trans-conformation in the meso-configuration.
    Notes: Die Reaktion von Tri-tert-butyl-cyclotriphosphan, (t-BuP)3, mit Phosphor(V)-chlorid (Molverhältnis 1:2) führt zu der Titelverbindung Cl(t-Bu)P—P(t-Bu)Cl (1), die gegenüber Disproportionierungsreaktionen bemerkenswert beständig ist. 1 wurde als erstes 1,2-Dichlor-1,2-diorganyldiphosphan in reiner Form isoliert und charakterisiert. Es liegt bei Raumtemperatur als Gemisch aus d,l- und meso-Form (etwa 20:80) vor. Die gegenseitige Abstoßung der negativ polarisierten Cl-Atome und deren bevorzugte gauche-Anordnung zu den freien Elektronenpaaren benachbarter P-Atome führt bei d,l-Konfiguration zu einer gauche- und bei meso-Konfiguration zu einer trans-Konformation der freien Elektronenpaare.
    Additional Material: 1 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/zaac.19824890103
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