ALBERT

All Library Books, journals and Electronic Records Telegrafenberg

X
feed icon rss

Your email was sent successfully. Check your inbox.

An error occurred while sending the email. Please try again.

Proceed reservation?

Export
Filter
  • Articles  (44)
  • Blackwell Publishing Ltd
  • 1995-1999  (44)
  • 1980-1984
  • 1925-1929
  • 1997  (44)
  • 1928
  • Physics  (44)
Collection
  • Articles  (44)
Source
Publisher
Years
  • 1995-1999  (44)
  • 1980-1984
  • 1925-1929
Year
Topic
  • 1
    Electronic Resource
    Electronic Resource
    Computer Simulations of Diffraction Effects due to Stacking Faults in β-SiC: I, Simulation Results (1997)
    Oxford, UK : Blackwell Publishing Ltd
    Journal of the American Ceramic Society 80 (1997), S. 0 
    Details
    ISSN: 1551-2916
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: X-ray diffraction (XRD) patterns from nominally β-SiC specimens often differ from those expected for the cubic crystal structure. These differences include the presence of additional peaks, enhanced background intensities, peak broadening, changes in relative peak heights, and shifts in peak positions. It has long been recognized that they are due to the presence of stacking faults, and models relating the experimental observations to stacking fault population have continued to evolve. The presence and relative magnitude of these features vary among different β-SiC specimens. In this work, computer simulations were used to show that the variations are closely related to differences in the type and spatial distribution of stacking faults in each specimen. In these simulations, stacking sequences were generated using a selectively activated 1-D Ising model with a Boltzmann-type probability function for specifying errors, which allows a wide variety of fault configurations to be generated. Direct correlations between different features in the XRD data to the underlying fault population are demonstrated, which are discussed in this paper. It is also shown that this computer model is general, in the sense that many of the models presented in prior work can be interpreted as limiting cases of it.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1151-2916.1997.tb03034.x
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 2
    Electronic Resource
    Electronic Resource
    Edge Stresses in Alumina/Zirconia Laminates (1997)
    Oxford, UK : Blackwell Publishing Ltd
    Journal of the American Ceramic Society 80 (1997), S. 0 
    Details
    ISSN: 1551-2916
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Using the technique of fluorescence piezospectroscopy, we determine the distribution of thermal residual stresses across the edges of three laminated alumina/zirconia composites. We develop a methodology for separating the measured stress state into microstresses that result from grain-to-grain thermal mismatch and macrostresses that result from lamination-induced thermal mismatch between individual plies. Comparison between the measured edge-stress distributions and those calculated based on a simple force-superposition model shows good agreement, indicating that the laminate system is well approximated as linear elastic. Given the experimental confirmation of significant edge stresses in multi-ply laminates, the possibility of failure initiating at composite edges must be considered in the design of surface-compressed laminate structures with the aim of mediating the detrimental effect of surface flaws.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1151-2916.1997.tb03031.x
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 3
    Electronic Resource
    Electronic Resource
    Nanostructuring of Laser-Deposited Ti Films by Self-Limited Oxidation (1997)
    Oxford, UK : Blackwell Publishing Ltd
    Journal of the American Ceramic Society 80 (1997), S. 0 
    Details
    ISSN: 1551-2916
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Local laser-induced oxidation of thin titanium films on glass is shown to be self-limiting due to a decrease in the absorptivity during the reaction. Taking advantage of this confinement, stable writing of transparent oxide line structures narrower than the diffraction-limited focused spot of a continuous wave Ar ion laser (500 nm) has been accomplished. The greatest optical contrast (1:10) with the highest resolution down to 165 nm was observed if the film thickness is of the order of the light absorption length in the metal.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1151-2916.1997.tb03035.x
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 4
    Electronic Resource
    Electronic Resource
    Debonding in Multilayered Composites of Zirconia and LaPO4 (1997)
    Oxford, UK : Blackwell Publishing Ltd
    Journal of the American Ceramic Society 80 (1997), S. 0 
    Details
    ISSN: 1551-2916
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Multilayered composites consisting of LaPO4 (La-monazite) layers alternating with various ZrO2-based materials were fabricated to investigate whether LaPO4 provides a weakly bonded interface suitable for promoting toughening, as previously observed in the system LaPO4/Al2O3. The following ZrO2-based materials were assessed: Y-ZrO2, Y-ZrO2/Al2O3, Ce-ZrO2, and Ce-ZrO2/Al2O3. Debonding was observed in all cases. The composites containing Y-ZrO2 and Y-ZrO2/Al2O3 were stable, with no reactions, at temperatures up to at least 1600°3C. However, in the composites containing Ce-ZrO2, interdiffusion of Ce and La occurred, resulting in formation of a pyrochlore-like phase and, in the case of the Ce-ZrO2/Al2O3 composite, a (Ce,La)Al11O18 magnetoplumbite phase.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1151-2916.1997.tb03038.x
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 5
    Electronic Resource
    Electronic Resource
    Structure and Mechanical Properties of Copper/Niobium Multilayers (1997)
    Oxford, UK : Blackwell Publishing Ltd
    Journal of the American Ceramic Society 80 (1997), S. 0 
    Details
    ISSN: 1551-2916
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Copper/niobium multilayers prepared by sputtering onto Si substrates with layer thicknesses ranging from 11 to 5000 Å have been characterized by transmission electron microscopy and nanoindentation. The films are strongly textured with {110} close-packed planes of the bcc Nb parallel to the {111} close-packed planes of the fcc Cu and close-packed directions tending to be parallel as well. For the 11 Å layers, the Cu is found to grow pseudomorphically on Nb in the bcc structure. It is thought that, for thicker layers, the bcc Cu loses coherency and transforms martensitically to the fcc phase, thus resulting in the observed Kurdjumov—Sachs orientation relationship. As the layer thickness, d, decreases from 5000 to 500 Å, the hardness increases as d-1/2; i.e., it follows a Hall—Petch relationship so that hardening is due to grain boundaries and interfaces. The slope is the same as in pure Cu, but there is a large intercept which is ascribed to internal stresses and a large dislocation density. As the layer thickness decreases from 100 to 11 Å, the hardness increases as (1/d) ln (0.69d), which is a line tension formulation such as would be expected for Orowan dislocation bowing between the layers. Again there is a large intercept which is ascribed to cutting through the Cu/Nb interfaces. The interfacial energy is calculated to be 0.46 J/m2.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1151-2916.1997.tb03037.x
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 6
    Electronic Resource
    Electronic Resource
    Microstructure Evolution of ZrO2-(Fe2O3, Al2O3) Materials Synthesized with Solution Precursors (1997)
    Oxford, UK : Blackwell Publishing Ltd
    Journal of the American Ceramic Society 80 (1997), S. 0 
    Details
    ISSN: 1551-2916
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Aqueous Zr-nitrate solutions containing appropriate amounts of Fe(NO3)3·6H2O and Al(NO3)3·6H2O were used to synthesize ZrO2-Fe2O3 compositions (up to 40 mol% Fe2O3) and one ZrO2-Al2O3-Fe2O3 composition. An amorphous phase was produced after pyrolysis, which subsequently crystallized to a single-phase Zr(Fe)O2 solid solution (or Zr(Fe,Al)O2 ss) that appeared cubic by X-ray diffraction, but tetragonal (c/a→ 1) by electron diffraction. The crystallization temperature increased with Fe2O3 content. At higher temperatures, the single phase partitioned to two phases, tetragonal-ZrO2+γ-Fe2O3. The γ- to α-Fe2O3 transformation occurred at still higher temperatures to produce a two-phase microstructure composed of two interpenetrating phases (ZrO2+α-Fe2O3), each with equiaxed grains. This microstructure was relatively stable to grain coarsening, even to temperatures just below the apparent eutectic temperature. With the exception of the lower transition temperatures and the equiaxed grains observed for both phases, these observations are similar to that previously reported for the ZrO2-Al2O3 system. The microstructure development reported here is another example for the synthesis via solution processing that involves diffusion-limited crystallization. Namely, a two-phase material can be produced where the grain size of each can be very small, and can be prevented from growing rapidly at high temperatures due to the constraint of each phase on one another.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1151-2916.1997.tb03039.x
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 7
    Electronic Resource
    Electronic Resource
    Mechanisms of High-Temperature Creep of Fully Stabilized Zirconia Single Crystals as a Function of the Yttria Content (1997)
    Oxford, UK : Blackwell Publishing Ltd
    Journal of the American Ceramic Society 80 (1997), S. 0 
    Details
    ISSN: 1551-2916
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: High-temperature creep behavior of yttria fully stabilized zirconia single crystals with various yttria contents in the interval 9.4 ≤x≤ 21 mol% has been studied. The mechanical data have been collected as a function of both the temperature and the yttria concentration. The creep behavior has been explained in terms of a transition between a dislocation viscous glide and a dislocation climb controlled mechanism, making use of a generalized version of a classical model for alloys proposed by Burton. The yttria concentration dependence of the creep rate has been connected with results on cationic diffusivity, with a possible influence of impurities.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1151-2916.1997.tb03036.x
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 8
    Electronic Resource
    Electronic Resource
    A Natural Ceramic/Polymer Layered Composite (1997)
    Oxford, UK : Blackwell Publishing Ltd
    Journal of the American Ceramic Society 80 (1997), S. 0 
    Details
    ISSN: 1551-2916
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: The examination of natural materials at the microscopic and microchemical level from a materials science perspective can occasionally suggest advances in modern materials engineering. The present paper reports on such a case: an analytical study of the detailed structure and composition of sea urchin teeth.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1151-2916.1997.tb03042.x
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 9
    Electronic Resource
    Electronic Resource
    Compression Test and Plastic Strain of α-Al2O3 Single Crystals (1997)
    Oxford, UK : Blackwell Publishing Ltd
    Journal of the American Ceramic Society 80 (1997), S. 0 
    Details
    ISSN: 1551-2916
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Compression tests of single crystals are analyzed with respect to shear due to the friction at the loaded ends. This simple approach permits an explanation of the features associated with prism plane slip in sapphire (α-Al2O3), i.e., the shape changes of the specimens and the curvature of the glide planes.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1151-2916.1997.tb03043.x
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 10
    Electronic Resource
    Electronic Resource
    Ferroelasticity of t‘-Zirconia: I, High-Voltage Electron Microscopy Studies of the Microstructure in Polydomain Tetragonal Zirconia (1997)
    Oxford, UK : Blackwell Publishing Ltd
    Journal of the American Ceramic Society 80 (1997), S. 0 
    Details
    ISSN: 1551-2916
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: The microstructure of polydomain tetragonal zirconia (t-ZrO2), i.e., a ZrO2 modification exhibiting ferroelastic behavior, is studied by high-voltage electron microscopy. This material consists of three domain variants of the tetragonal phase with their c-axes nearly orthogonal to each other. Always two variants of these platelike domains are alternately arranged, forming elongated regular colonies. Hence, in both variants the common habit plane of the domains is a {110} twin plane. The colonies are of columnar shape with a longitudinal axis. They are bound by {110} planes, too, which are twin planes for the domains in the contiguous colonies. Owing to their particular structure and the helical arrangement of the adjoining colonies, the material remains coherent and pseudocubic over large macroscopic regions, although it is formed by different tetragonal domains.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1151-2916.1997.tb03040.x
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 11
    Electronic Resource
    Electronic Resource
    Ferroelasticity of t‘-Zirconia: II, In situ Straining in a High-Voltage Electron Microscope (1997)
    Oxford, UK : Blackwell Publishing Ltd
    Journal of the American Ceramic Society 80 (1997), S. 0 
    Details
    ISSN: 1551-2916
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: The ferroelastic deformation of t-ZrO2, the microstructure of which was described in detail in Part I, was investigated by in situ deformation experiments in the high-voltage electron microscope at 1150°3C. During the experiments those two domain variants with their c-axes perpendicular to the [010] tensile direction were transformed into the third one with its c-axis parallel to the tensile direction. The subsequent ‘switching’ of the domains inside the colonies proceeds much faster than the penetration of the transformation front into a neighboring colony. Therefore, the transformed region, exhibiting a unique tetragonal structure and containing residual defects, preferentially expands into the longitudinal directions of the colonies. The transformation of single domains proceeds instantaneously within the time resolution of the video tape recording.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1151-2916.1997.tb03041.x
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 12
    Electronic Resource
    Electronic Resource
    Agglomeration during the Drying of Fine Silica Powders, Part II: The Role of Particle Solubility (1997)
    Oxford, UK : Blackwell Publishing Ltd
    Journal of the American Ceramic Society 80 (1997), S. 0 
    Details
    ISSN: 1551-2916
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: The effect of particle solubility and the dissolution rate on agglomeration was studied by drying silica and titania particles from aqueous slurries with pH values in the range of 2–12. The agglomerate strength and strength distribution were measured by a calibrated ultrasonic force, and the strength increased as the solubility and dissolution rate increased. Two silica powders of different particle size (60 nm and 500 nm) were studied, and smaller-sized particles formed stronger agglomerates. The drying rate of the powders was varied by using spray drying and tray drying, and slower drying was shown to lead to higher agglomerate strength. The agglomerate strength of titania powder (insoluble in water) was independent of pH, whereas the agglomerate strength of silica was dependent on pH. It was concluded that the solubility and dissolution rate are important parameters that govern the strength of agglomerates.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1151-2916.1997.tb03044.x
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 13
    Electronic Resource
    Electronic Resource
    Formation Kinetics of MoSi2 and Mo5Si3 by the Reactive Diffusive Siliciding of Molybdenum (1997)
    Oxford, UK : Blackwell Publishing Ltd
    Journal of the American Ceramic Society 80 (1997), S. 0 
    Details
    ISSN: 1551-2916
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: The formation kinetics of products formed by the reaction between dense molybdenum and vapor-supplied silicon at an activity approximating that of solid silicon under open flowing gas conditions was studied at 1200°3C. An outer MoSi2 layer overlaid the much thinner Mo5Si3 that formed on the molybdenum. Both phases obeyed parabolic growth laws over a 22 h period, having parabolic rate constants of 6.8 times 10-10 cm2/s for the MoSi2 and 1.3 times 10-13 cm2/s for the Mo5Si3 phases. These results were ∼2 orders of magnitude less than prior results, mostly obtained by another processing route. Possible explanations include enhanced growth rates from chemical contamination. Gross distortion and abnormal layer thicknesses at specimen edges and the 159% volume increase during siliciding suggest that the kinetics also are strain dependent.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1151-2916.1997.tb03045.x
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 14
    Electronic Resource
    Electronic Resource
    Origin of the Positive Temperature Coefficient of Resistivity Anomaly in the ZnO-NiO System (1997)
    Oxford, UK : Blackwell Publishing Ltd
    Journal of the American Ceramic Society 80 (1997), S. 0 
    Details
    ISSN: 1551-2916
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: An anomalous positive temperature coefficient of resistivity (PTCR) was investigated in the ZnO-NiO system. It was found that the ZnOSS (Zn0.97Ni0.03O) and NiOSS (Ni0.6Zn0.4O) constituent phases of that system exhibit negative temperature coefficient of resistivity (NTCR) character, while their combination shows a PTCR effect with a maximum at 400°3C, which coincides with a large difference in the coefficient of linear thermal expansion between the ZnOSS and NiOSS phases at that temperature. On the basis of the brick wall model microstructure, the PTCR anomaly of this system can be explained. The magnitude of the PTCR effect is governed by the difference in resistivity of the two constituent phases at the temperature where the maximum of the PTCR anomaly occurs. The predicted temperature dependence of the resistance, R(T), of a model microstructure consisting of constituent phases with different grain sizes agrees well with the experimental R(T) of the prepared composite ceramics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1151-2916.1997.tb03047.x
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 15
    Electronic Resource
    Electronic Resource
    Effect of Ordering-Induced Domain Boundaries on Low-Loss Ba(Zn1/3Ta2/3)O3-BaZrO3 Perovskite Microwave Dielectrics (1997)
    Oxford, UK : Blackwell Publishing Ltd
    Journal of the American Ceramic Society 80 (1997), S. 0 
    Details
    ISSN: 1551-2916
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Small substitutions of BaZrO3 into Ba[(Zn,Ni)1/3Ta2/3]O3 are utilized in the commercial preparation of low-loss perovskite microwave dielectrics. The structures of a series of these phases with substitution levels ranging from 1% to 5% BaZrO3 were examined using high-resolution TEM. For ≤ 2.15% BaZrO3 the solid solutions retain the ordered “1:2” structure of the Ba[(Zn,Ni)1/3Ta2/3]O3 end-member but are comprised of small ordered domains whose size decreases as the Zr content is raised. The decrease in the size of the domains parallels a decrease in the processing time required to access a low-loss state. Although for pure Ba[(Zn,Ni)1/3Ta2/3]O3 reductions in the degree of cation order produce a large increase in the dielectric loss, the Zr-substituted ceramics retain a very low loss. We believe the low losses of the 1:2 ceramics are derived from the stabilization of the ordering-induced domain boundaries via the partial segregation of the Zr cations. For substitutions between 3% and 5% BaZrO3 the size of the ordered domains continues to decrease but the system undergoes an abrupt transformation to a cubic “1:1” ordered structure with a doubled perovskite repeat. The structures of these phases have been interpreted using a “random layer” model in which one site is occupied by Ta and the other by a random distribution of Zn, Zr, and the remaining Ta cations, i.e., Ba{[Zn(2-y)/3Ta(1–2y)/3Zry]1/2[Ta1/2]}O3. Although the ordering is confined to nano-sized domains, these ceramics also exhibit low losses, again reflecting the relative stability of the domain boundaries. In this case we believe the low losses reflect the effectiveness of the random layer in stabilizing the anti-phase boundaries.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1151-2916.1997.tb03046.x
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 16
    Electronic Resource
    Electronic Resource
    Oxidation of Single Crystals of Hafnium Carbide in a Temperature Range of 600° to 900°3C (1997)
    Oxford, UK : Blackwell Publishing Ltd
    Journal of the American Ceramic Society 80 (1997), S. 0 
    Details
    ISSN: 1551-2916
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: The isothermal oxidation of HfC single crystals with (100) orientation was carried out using an electromicrobalance at temperatures of 600° to 900°3C at an oxygen pressure of 2 to 8 kPa. Nonisothermal oxidation was performed by a simultaneous thermogravimetry—differential thermal analysis—mass spectrometry analysis. A polished cross section of the oxidized crystal was observed by backscattered electron imaging in a scanning electron microscope. Quantitative chemical analysis for Hf, O, and C and their elemental profiles in the HfC and oxide scale was carried out by wavelength dispersive X-ray microanalysis. It was found that the oxide scale consists of two regions, zones 1 and 2, both of which showed the existence of carbon. The carbon content at the middle point of zone 1 was about twice that in zone 2, which contained 7 to 14 at.% carbon. Zone 1 showed an almost compact and pore-free phase; its thickness remained constant (1 to 2 μm) after a prolonged time. The thickness of zone 2 increased linearly with time. The oxidation mechanism including interfacial reaction responsible for the deposition of carbon is discussed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1151-2916.1997.tb03048.x
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 17
    Electronic Resource
    Electronic Resource
    Feasibility of Using Cordierite Glass-Ceramics as Tile Glazes (1997)
    Oxford, UK : Blackwell Publishing Ltd
    Journal of the American Ceramic Society 80 (1997), S. 0 
    Details
    ISSN: 1551-2916
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Basic principles of fabricating tile glazes based on cordieritic glass-ceramics are explained. Glass compositions from the MgO-Al2O3-SiO2 three-component phase diagram have been melted with and without the nucleating agent TiO2. Additionally, a sodium borosilicate glass that is commonly used in the tile glaze industry has been wet milled, together with the previous compositions, to produce a coating slip. Studies are focused on the role of the nucleating agent and glassy formulation in the crystallization of the glass-ceramic system using differential thermal analysis, X-ray diffractometry, and scanning electron microscopy. When added to a borosilicate glass, only one composition is capable of crystallizing cordierite under a fast-firing cycle used for “monoporosa” production. The porosity of the glaze layer is sufficiently low and the crystal size is small to ensure good mechanical and chemical properties. The presence of cordierite crystals in the glaze should enhance abrasion and acid resistance, in comparison to a traditional matte glaze that contains mostly enstatite or diopside crystals.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1151-2916.1997.tb03049.x
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 18
    Electronic Resource
    Electronic Resource
    Synthesis of Ba2NaNb5O15 Powders and Thin Films Using Metal Alkoxides (1997)
    Oxford, UK : Blackwell Publishing Ltd
    Journal of the American Ceramic Society 80 (1997), S. 0 
    Details
    ISSN: 1551-2916
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Transparent and highly oriented Ba2NaNb5O15 (BNN) thin films have been prepared by using metal alkoxides. A homogeneous precursor solution was prepared by the controlled reaction of NaOC2H5, Nb(OC2H5)5, and barium metal. The BNN precursor included a molecular-level mixture of NaNb(OC2H5)6 and Ba[Nb(OC2H5)6]2 in ethanol. The alkoxy-derived powder crystallized to a low-temperature phase, and then transformed to orthorhombic BNN (tungsten bronze) at 600°3C. BNN precursor films on substrates crystallized to orthorhombic BNN at 800°3C via the low-temperature phase. Highly (002) oriented BNN films of tungsten bronze structure were successfully prepared on MgO (100) substrates at 700°3C by using BNN underlayer.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1151-2916.1997.tb03050.x
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 19
    Electronic Resource
    Electronic Resource
    Aqueous Processing of Sintered Reaction-Bonded Silicon Nitride: I, Dispersion Properties of Silicon Powder (1997)
    Oxford, UK : Blackwell Publishing Ltd
    Journal of the American Ceramic Society 80 (1997), S. 0 
    Details
    ISSN: 1551-2916
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: An aqueous-based system (Si-Al2O3-Y2O3-Fe2O3) for processing sintered reaction-bonded silicon nitride (SRBSN) was investigated with an emphasis on chemical control of suspension component interactions. Chemical stability and dispersion properties of a commercial silicon powder were characterized using electroacoustic, adsorption isotherm, and rheological measurements. The interactions of silicon with nitriding agent, sintering aids, dispersants, and binder were considered. The effects of pH, electrolyte, aging, particle size, and solids loading were examined. The suspension properties of the silicon powder were influenced by the native oxide film and powder treatment history. The silicon—oxide composite particles exhibit dispersion behavior similar to silica, characterized by a negative surface potential above pH 2. A method to improve the dispersion and homogeneity of suspension components based on the use of quaternary amine dispersants is proposed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1151-2916.1997.tb03052.x
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 20
    Electronic Resource
    Electronic Resource
    Computer Simulation of Grain Growth and Ostwald Ripening in Alumina—Zirconia Two-Phase Composites (1997)
    Oxford, UK : Blackwell Publishing Ltd
    Journal of the American Ceramic Society 80 (1997), S. 0 
    Details
    ISSN: 1551-2916
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: The kinetics of grain growth and Ostwald ripening in Al2O3-ZrO2 two-phase composites was systematically investigated using two-dimensional (2-D) computer simulations, based on a diffuse-interface field model. Using average values for the experimentally measured ratios of the grain boundary energies to the interphase boundary energy as the input, the predicted 2-D microstructural features and their evolution are in excellent qualitative agreement with experimental observations on 2-D cross sections of 3-D Al2O3-ZrO2 two-phase composite microstructures. It was found that the coupled grain growth in Al2O3-ZrO2 composites is controlled by long-range diffusion and the average size (Rt) as a function of time (t) follows the power-growth law, Rmt - Rm0=kt with m= 3, which is independent of the initial microstructures and volume fractions of the two phases. The predicted variation of the kinetic coefficient (k) on the volume fraction follows a trend similar to that experimentally measured through the entire range of volume fractions. The scaling of grain size distributions is observed at a given volume fraction, i.e., they are time-invariant in the steady state. However, the characteristics of size distributions vary with the initial microstructures and the volume fractions. The relationship between matrix grain size and second-phase grain size is discussed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1151-2916.1997.tb03051.x
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 21
    Electronic Resource
    Electronic Resource
    Thermally Induced Reversible Coagulation in Ceramic Powder-Polymer Liquid Suspensions (1997)
    Oxford, UK : Blackwell Publishing Ltd
    Journal of the American Ceramic Society 80 (1997), S. 0 
    Details
    ISSN: 1551-2916
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: It was observed that slurries of oxide powders in oxidized polybutene fluids can be caused to change reversibly between fluid, nearly Newtonian behavior and plastic behavior by modest changes in temperature. This phenomenon was believed to result from changes in the dispersion vs association among the particles. The rheological effects of temperature, polymer oxidation, and particle size were observed for 30 vol% slurries of TiO2, Al2O3, and ZrO2 powders in polybutene fluids. Elasticity (in oscillation) and low-shear-rate viscosity (in steady shear) were observed to increase with increasing temperature for TiO2 and Al2O3 particles in oxidized polybutene fluids. This behavior was attributed to the creation of interparticle structures. The attainment of this structure on heating was observed to be inhibited by increased oxidation of the polymer and increased particle size. It was concluded that the adsorption of oxidized molecules from the polymer liquid, along with the high viscosity of the bulk polymer, resulted in suspensions that were metastable against coagulation. Increased temperature resulted in lower viscosities of the liquid, allowing coagulation on a short time scale. The presence of the adsorbed polymer, however, prevented intimate contact among the particles so that the coagulated structure was easily destroyed upon subsequent cooling and shearing.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1151-2916.1997.tb03053.x
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 22
    Electronic Resource
    Electronic Resource
    Minimizing Infiltration Times during Isothermal Chemical Vapor Infiltration with Methyltrichlorosilane (1997)
    Oxford, UK : Blackwell Publishing Ltd
    Journal of the American Ceramic Society 80 (1997), S. 0 
    Details
    ISSN: 1551-2916
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Minimum infiltration times during isothermal chemical vapor infiltration were calculated for the formation of a silicon carbide matrix composite from methyltrichlorosilane (MTS). Several different reaction models were used to describe the SiC deposition kinetics. The results show that the nature of the reaction model has a significant effect on process optimization considerations. It is clear that a simple first-order deposition reaction does not accurately describe the infiltration process, while rate expressions that treat the effect of chlorine-containing byproduct gases provide much more accurate predictions. In theory, much shorter infiltration times can be obtained with precursor chemistries that do not produce Cl-containing gases. The results also provide guidelines for minimizing infiltration times with MTS.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1151-2916.1997.tb03055.x
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 23
    Electronic Resource
    Electronic Resource
    High-Temperature Transverse Fracture Toughness of Nicalon-Fiber-Reinforced CAS-II Glass-Ceramic Matrix Composite (1997)
    Oxford, UK : Blackwell Publishing Ltd
    Journal of the American Ceramic Society 80 (1997), S. 0 
    Details
    ISSN: 1551-2916
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Cracking parallel to the fibers in off-axis plies is usually the initial form of damage in composite laminates. This cracking process has been associated with the (transverse) fracture toughness, defined by the critical strain energy release rate, GIc. The measurement of GIc provides basic information about the transverse crack resistance. In this study, the utility of the double torsion (DT) test technique to determine GIc in a glass-ceramic matrix composite (Nicalon/CAS-II) at temperatures up to 1000°3C has been demonstrated. GIc did decrease moderately with increasing temperature (as does the bulk matrix); however, no evidence of an interphase oxidizing effect on crack growth (parallel to the fibers) could be found. The inevitable misalignment of fibers in the material was not very efficient at bridging the crack in the DT specimens, in contrast to the significant matrix crack interactions with the fibers reported for other geometries such as double cantilever beam and flexure specimens.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1151-2916.1997.tb03056.x
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 24
    Electronic Resource
    Electronic Resource
    Reaction Sequence in the Preparation of NiAl2O4 Spinel—Mullite Composites by Sol—Gel (1997)
    Oxford, UK : Blackwell Publishing Ltd
    Journal of the American Ceramic Society 80 (1997), S. 0 
    Details
    ISSN: 1551-2916
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: NiAl2O4 spinel—mullite composites were prepared by simultaneous replacement of Al by Ti and/or Ni in 3:2 stoichiometric mullite. Specimens having nominal compositions 3(Al2-2xNixTixO3) · 2SiO2 (x= 0, 0.025, 0.05, 0.2) and 3(Al2-xMxO3) · 2SiO2 (M = Ni2+ or Ti4+ and x= 0.05) were synthesized by sol—gel techniques, which provide homogeneous gels in the SiO2-Al2O3 system. Gel structures investigated by infrared (IR) spectroscopy revealed the formation of Al-O-Si bonds in dried gels. The reaction sequence of gel-derived glasses, previously obtained by preheating gels at 750°3C for 3 h, was evaluated by X-ray powder diffraction (XRD) and ultraviolet—visible (UV—vis) spectroscopy. All samples crystallized at around 1000°3C from an amorphous state, but unexpectedly the first crystalline phase was Al-Si spinel in all aluminum-substituted specimens; i.e., a change in the sequence of reaction with respect to the 3:2 stoichiometric mullite was produced. NiAl2O4 spinel was almost simultaneously detected. Two processes of mullite crystallization were observed. The temperature of formation of mullite was the lowest for the higher substituted sample. The microstructure of the final NiAl2O4 spinel—mullite composites found in all Ni-containing samples after annealing for 96 h was examined by scanning electron microscopy with energy dispersive X-ray analysis (SEM/EDX), which revealed the presence of small particles of NiAl2O4 spinel dispersed in a mullite matrix. For annealed compositions with the larger Al replacement, i.e., when x= 0.2, a small amount of very small Al2TiO5 particles was also detected by XRD and transmission electron microscopy (TEM).
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1151-2916.1997.tb03054.x
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 25
    Electronic Resource
    Electronic Resource
    Influence of the Oxide Precursors on the Reaction Sequencing and Kinetics in the Yttrium—Barium—Copper—Oxygen System (1997)
    Oxford, UK : Blackwell Publishing Ltd
    Journal of the American Ceramic Society 80 (1997), S. 0 
    Details
    ISSN: 1551-2916
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: The reactions of stoichiometric Y2O3, CuO, and different barium salts (BaCO3, Ba(NO3)2, BaO2, BaCuO2) for forming various compounds in the yttrium—barium—copper—oxygen system (i.e., YBa2Cu3O7–8, BaCuO2, Y2BaCuO5, and Y2Cu2O5) were systematically investigated by thermal analysis and X-ray diffractometry. In a few cases, the relevant activation energies were calculated. The reaction pathway and kinetics were significantly dependent on the physicochemical and thermal stability of the barium precursors, as well as on the crystalline size of the reagent. Binary BaO-CuO phases formed at low temperature (650°-700°3C) when in the presence of easy-to-decompose barium precursors, and then slowly transformed to ternary compounds; in contrast, when barium ions were released at temperatures of 〉900°3C, ternary phases formed directly from the components.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1151-2916.1997.tb03057.x
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 26
    Electronic Resource
    Electronic Resource
    Fiber-Reinforced Ceramic-Matrix Composites with a Polysiloxane/Boron-Derived Matrix (1997)
    Oxford, UK : Blackwell Publishing Ltd
    Journal of the American Ceramic Society 80 (1997), S. 0 
    Details
    ISSN: 1551-2916
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: A ceramic matrix for carbon-fiber-reinforced ceramic-matrix composites (CMCs) has been developed from poly-siloxane/boron mixtures. Complex geometries can be realized by using standard technologies of fiber-reinforced polymer composites. On pyrolysis, the polymer—filler mixture is converted to a ceramic matrix, consisting of silicon carbide, boron carbide, boron nitride, and a silicon oxycarbide (SiOC) glass, without reacting with the carbon fiber. Because of the large volume increase of the boron filler on nitridation (142 vol%), no multiple reinfiltration of the structure is necessary to achieve a dense matrix. Tensile strength and interlaminar shear strength exhibit maxima at a pyrolysis temperature of 1300°3C, where extensive fiber pullout is observed. Thermodynamic calculations have been used to evaluate the theoretical qualitative and quantitative phase compositions at equilibrium. Thermoanalytical (thermogravimetry—mass spectroscopy) and structural analysis (X-ray diffractometry) have shown a satisfying coherence with respect to the condensed phases, whereas deviations have been noted with respect to the composition of the gas phase.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1151-2916.1997.tb03058.x
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 27
    Electronic Resource
    Electronic Resource
    Effect of Carbohydrate on the Rheological Parameters of Paste Extrusion (1997)
    Oxford, UK : Blackwell Publishing Ltd
    Journal of the American Ceramic Society 80 (1997), S. 0 
    Details
    ISSN: 1551-2916
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Carbohydrates are often key components in the formulation of extrusion pastes, yet the reasons for selection are presently empirical. The influence on paste extrusion of various types of carbohydrates, such as starch, dextrin, lactose, and glucose, have been studied and related to their water retention capacities. The bulk yield stress and the surface shear stress both decrease as the moisture content increases; however, the way in which the water that is present interacts with the carbohydrate has an important influence. The behavior of some carbohydrates can be substantially accounted for by a consideration of packing effects; however, dextrin behaves differently. The carbohydrates function not only as a binder but also as a means of retaining the liquid phase.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1151-2916.1997.tb03059.x
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 28
    Electronic Resource
    Electronic Resource
    Spherical Indentation and Fracture of Glass Plates (1997)
    Oxford, UK : Blackwell Publishing Ltd
    Journal of the American Ceramic Society 80 (1997), S. 0 
    Details
    ISSN: 1551-2916
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Spherical indentation of thick and thin glass plates was investigated numerically and experimentally. The energy release rate at the tip of a cone crack was calculated by using finite element techniques and used to investigate the applicability in thick plates of Roesler's law relating the cone crack radius to the indentation load. Indentations of thin glass specimens resting on different substrates were also studied numerically and experimentally. The stresses in the thin specimens were calculated and correlated with the observed failures. On the basis of these results, a crack initiation mechanism map was developed for glass specimens on different substrates.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1151-2916.1997.tb03060.x
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 29
    Electronic Resource
    Electronic Resource
    Quantitative Characterization of Indentation Crack Path in a Cubic Zirconia—10 vol% Alumina Composite (1997)
    Oxford, UK : Blackwell Publishing Ltd
    Journal of the American Ceramic Society 80 (1997), S. 0 
    Details
    ISSN: 1551-2916
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Stereological measurements were performed to characterize the indentation crack path in a cubic zirconia—10 vol% alumina (c-ZrO2-10 vol% Al2O3) composite. Cracks were generated using Vickers indentation, and the crack propagation behavior was characterized as a function of the indentation loading/unloading rates. Cracks that were produced by Vickers indentation formed at higher crack velocities as the loading/unloading rates increased. The amount of contact between the crack and the Al2O3 particles increased as the indentation rate decreased. The total number of crack—particle interactions per unit crack length also increased as the indentation rate decreased, because of an increase in the number of particles that were fractured per unit crack length, whereas the number of particles that were debonded remained relatively constant as the indentation rate changed. These results suggest that residual thermal mismatch stresses have predominant control of the crack path at lower crack velocities (low indentation loading/unloading rate), whereas elastic mismatch stresses predominate at higher crack velocities (high indentation loading/unloading rate).
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1151-2916.1997.tb03061.x
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 30
    Electronic Resource
    Electronic Resource
    X-ray Photoemission and Energy Dispersive Spectroscopy of Hydroxyapatite-Coated Titanium (1997)
    Oxford, UK : Blackwell Publishing Ltd
    Journal of the American Ceramic Society 80 (1997), S. 0 
    Details
    ISSN: 1551-2916
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: The purpose of this study was to determine the chemical composition changes of hydroxyapatite (HA) coated titanium using surface analysis (X-ray photoemission) and bulk analysis (energy dispersive spectroscopy). The specimens examined were controls and specimens aged 30 min and 3 h at room temperature in distilled water and 0.2M sodium phosphate buffer (pH 7.2). Each X-ray photoemission cycle consisted of three scans followed by argon sputtering for 10 min for usually 20 cycles, corresponding to a sampling depth of ∼1500 Å. The energy dispersive spectroscopy analysis was on a 110 by 90 μm area for 500 s. The X-ray photoemission results indicated the oxidation effect of water on the titanium (as TiO2) and the effect of the buffer to increase the surface concentration of phosphorus. No differences in the chemical composition were observed by energy dispersive spectroscopy analysis.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1151-2916.1997.tb03062.x
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 31
    Electronic Resource
    Electronic Resource
    In Situ Reacted Rare-Earth Hexaaluminate Interphases (1997)
    Oxford, UK : Blackwell Publishing Ltd
    Journal of the American Ceramic Society 80 (1997), S. 0 
    Details
    ISSN: 1551-2916
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: A novel in situ reaction between a ceria-doped zirconia interphase coating on Saphikon fibers and an outer alumina coating has resulted in the formation of oriented hexaaluminate platelets which can act as a low fracture energy interface barrier for crack deflection in oxide—oxide ceramic-matrix composites (CMCs). The reaction proceeds only in reducing environments where the reduction of the cerium and zirconium ions to their 3+ valent state causes a destabilization phenomenon consistent with previously reported findings. The diffusion of the cerium from the zirconia into solid solution with the alumina can stabilize the layered hexaaluminate structure. Preferred orientational growth of the hexaaluminate parallel to the coating interface was observed which is the required orientation for enhanced debonding at the fiber/matrix interface in long-fiber-reinforced CMCs.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1151-2916.1997.tb03063.x
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 32
    Electronic Resource
    Electronic Resource
    Strengthening of Alumina by Formation of a Mullite/Glass Layer on the Surface (1997)
    Oxford, UK : Blackwell Publishing Ltd
    Journal of the American Ceramic Society 80 (1997), S. 0 
    Details
    ISSN: 1551-2916
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: A layer composed of mullite and silicate glass was caused to form on the surface of a high-purity alumina ceramic in order to enhance the strength of the material. The layer was formed by exposing the specimens above a bed of SiC platelets at 1400°3C to a flowing H2 atmosphere containing ∼0.1% H2O. A reaction between the SiC platelets and the H2O in the environment resulted in the generation of SiO gas. Some of the SiO gas subsequently reacted with ambient H2O in the atmosphere, forming SiO2“smoke” which was deposited on, and reacted with, the alumina substrate. The strength of the ceramic was significantly improved by the reaction layer, which was found to be comprised of mullite and silicate glass. The increases in strength (about 60% above that of the material in the “as-polished” condition) was attributed to the blunting of surface cracks. A similar strengthening effect was observed in samples of the material which had been ground with a 220-grit diamond abrasive wheel (as had all of the samples) but not polished.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1151-2916.1997.tb03064.x
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 33
    Electronic Resource
    Electronic Resource
    Differential Negative Resistance and Piezoresistivity in Thin Semiconducting BaTiO3 Ceramic Bars (1997)
    Oxford, UK : Blackwell Publishing Ltd
    Journal of the American Ceramic Society 80 (1997), S. 0 
    Details
    ISSN: 1551-2916
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Thin, semiconducting barium titanate (BaTiO3) ceramic bars, with a diameter of 10 to 20 μm, consisting of single grains joined together in series have been prepared to investigate the piezoresistivity in the materials, which was evaluated from their current (I)-voltage (V) characteristics under the loading condition of various bending stresses. I-V characteristics of single grain boundaries in some of the materials were found to exhibit distinct differential negative resistance (DNR) at room temperature with its feature changing with stress. The DNR appeared on the I-V curves at an electric field of several volts per one grain, and has been confirmed to be connected with the transition of current between two conduction states in the grain boundary region. The obtained results indicate that this phenomenon cannot be interpreted by a rise in the temperature of the materials up to their positive temperature coefficient of resistivity (PTCR) region above the Curie point by Joule heating due to current flow, that is their self-heating effect. This newly observed DNR phenomenon has thus been tentatively interpreted by the morphological change in the ferroelectric domain structure in the vicinity of grain boundaries under mechanical and electric stresses, on an assumption that different configurations of ferroelectric domains yield different conduction states in the grain boundary due to a difference in the degree of surface acceptor charge compensation or the anisotropic carrier mobilities in the crystal.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1151-2916.1997.tb03065.x
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 34
    Electronic Resource
    Electronic Resource
    Effect of Porosity and Grain Size on the Microwave Dielectric Properties of Sintered Alumina (1997)
    Oxford, UK : Blackwell Publishing Ltd
    Journal of the American Ceramic Society 80 (1997), S. 0 
    Details
    ISSN: 1551-2916
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: The real part of the permittivity (ε) and the tan δ of sintered alumina (Al2O3) at about 9 GHz have been measured. The dielectric properties have been examined as a function of purity, pore volume, and sintered grain size. The tan δ is found to depend very strongly on the pore volume, purity, and grain size. ε is far less sensitive to impurities and grain size. The dependence of ε on porosity can be described by simple mixture models as expected. A model of losses in single crystals cannot be extended easily to these materials where extrinsic factors such as porosity, random crystal orientation, grain boundaries, microcracks, and impurities dominate. These factors have been studied in an attempt to describe the tan δ and ε of sintered polycrystalline alumina. In this work, the tan δ for alumina has been studied in near-theoretical density ranges between 9.1 times 10-5 and 2.4 times 10-5 depending on grain size.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1151-2916.1997.tb03066.x
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 35
    Electronic Resource
    Electronic Resource
    A Discernible Dielectric Aging Effect in the Undoped, N2-H2-Annealed Lead Magnesium Niobate—Lead Titanate Ceramic (1997)
    Oxford, UK : Blackwell Publishing Ltd
    Journal of the American Ceramic Society 80 (1997), S. 0 
    Details
    ISSN: 1551-2916
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: It is well known that the undoped Pb(Mg1/3Nb2/3)O3-PbTiO3 ceramics, prepared through conventional ceramic processing, present no evident aging effect. In this paper, however, a discernible aging phenomenon was observed in an undoped, N2-H2-annealed ceramic. When this sample was later annealed again in air, this effect became negligible again just like that of a normally prepared PMN—PT ceramic. The valence states of Ti ions, which may be changeable in different annealing atmospheres, were assumed to be responsible for the different degrees of aging.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1151-2916.1997.tb03067.x
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 36
    Electronic Resource
    Electronic Resource
    Model Experiment on Thermodynamic Stability of Retained Intergranular Amorphous Films (1997)
    Oxford, UK : Blackwell Publishing Ltd
    Journal of the American Ceramic Society 80 (1997), S. 0 
    Details
    ISSN: 1551-2916
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: To test the stability of intergranular amorphous films against crystallization, a model experiment was conducted wherein a thin SiO2 film was deposited on a single-crystal TiO2 substrate, annealed to form a eutectic liquid in equilibrium with the substrate, then quenched and crystallized below the eutectic temperature. This geometry is free of residual stresses and capillary effects proposed by others as kinetic limitations to complete crystallization. Furthermore, using a binary system removes solute rejection barriers to complete crystallization. A remnant amorphous film ∼1.5 nm thick retained at the hetero-interface shows unequivocally that the amorphous film is thermodynamically preferred to a crystal/crystal interface in this system.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1151-2916.1997.tb03068.x
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 37
    Electronic Resource
    Electronic Resource
    Fast Li+ Ion Conduction in Li2O-Al2O3-TiO2-SiO2-P2O2 Glass-Ceramics (1997)
    Oxford, UK : Blackwell Publishing Ltd
    Journal of the American Ceramic Society 80 (1997), S. 0 
    Details
    ISSN: 1551-2916
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Fast lithium ion conducting glass-ceramics have been successfully prepared from the pseudobinary system 2[Li1+xTi2SixP3-xO2]-AlPO4. The major phase present in the glass-ceramics was LiTi2P3O12 in which Ti4+ ions and P5+ ions were partially replaced by Al3+ ions and Si4+ ions, respectively. Increasing x resulted in a considerable enhancement in conductivity, and in a wide composition range extremely high conductivity over 10-3 S/cm was obtained at room temperature.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1151-2916.1997.tb03070.x
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 38
    Electronic Resource
    Electronic Resource
    Three-Dimensional Carbon/Silicon Carbide Composites Prepared by Chemical Vapor Infiltration (1997)
    Oxford, UK : Blackwell Publishing Ltd
    Journal of the American Ceramic Society 80 (1997), S. 0 
    Details
    ISSN: 1551-2916
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Continuous-carbon-fiber-reinforced silicon carbide composites (C/SiC) were prepared by chemical vapor infiltration in which the preforms were fabricated with the three-dimensional braid method. The mechanical properties and microstructures were investigated. For the composites with no interfacial layer, flexural strength and fracture toughness increased with density of the composites, and the maximum values were 520 MPa and 16.5 MPa·m1/2, respectively. The fracture behavior was dependent on the interfacial bonding between fiber/matrix and fiber bundle/bundle which was determined by the density of the composites. Heat treatment had a significant influence on the mechanical properties and fracture behavior. The composites with pyrolysis interfacial layers exhibited characteristic fracture and relatively low strength (300 MPa).
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1151-2916.1997.tb03069.x
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 39
    Electronic Resource
    Electronic Resource
    Fracture Toughness Evaluation of Small Thin Ceramic Specimens (1997)
    Oxford, UK : Blackwell Publishing Ltd
    Journal of the American Ceramic Society 80 (1997), S. 0 
    Details
    ISSN: 1551-2916
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: A test method to evaluate the fracture toughness, KIC, of thin, small, precracked ceramic specimens is described. The method is applicable for thin plates, wafers, self-supported layers, etc., especially when a large amount of material is not available for testing. The method consists of bonding a small, thin single-edge notched beam on one side of a metallic beam. A stress-free precrack with a square root singularity is achieved when the assembly is deformed in three-point bending.The fracture toughness of a thin, alumina single-edge precracked beam was evaluated experimentally using this method, and compared with that obtained for similar specimens having a 0.3-mm-wide machined notch. Comparison with previously reported fracture toughness values suggests that even a very sharp machined notch overestimates the evaluated fracture toughness.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1151-2916.1997.tb03071.x
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 40
    Electronic Resource
    Electronic Resource
    Dielectric Depression and Dispersion in Electrophoretically Fabricated BaTiO3 Ceramic Films (1997)
    Oxford, UK : Blackwell Publishing Ltd
    Journal of the American Ceramic Society 80 (1997), S. 0 
    Details
    ISSN: 1551-2916
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Dielectric depression and dispersion were observed in BaTiO3 ceramic films fabricated by electrophoretic deposition followed by sintering. The dielectric constants were depressed down to 6800-4600 around the Curie point (TC). The dielectric dispersion occurred above TC. These dielectric properties are attributable to a surface layer formed during sintering. XRD analysis indicated that the surface layer was a hexagonal-like BaTiO3 phase. A mixed solvent of acetylacetone and alcohol employed in the present work may have been responsible for the formation of the surface layer.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1151-2916.1997.tb03072.x
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 41
    Electronic Resource
    Electronic Resource
    Characterization of the Cotunnite-Type Phases of Zirconia and Hafnia by Neutron Diffraction and Raman Spectroscopy (1997)
    Oxford, UK : Blackwell Publishing Ltd
    Journal of the American Ceramic Society 80 (1997), S. 0 
    Details
    ISSN: 1551-2916
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: The crystal structures of the cotunnite-type phases (space group, Pnam, Z= 4) of pure zirconia and hafnia prepared under high-temperature, high-pressure conditions in a multianvil device were refined by time-of-flight neutron powder diffraction. The structures of both compounds are very similar and the nine polyhedral metal-oxygen distances range from 2.133(1) to 2.546(1) Å in ZrO2 and from 2.121(1) to 2.535(2) Å in HfO2. The Raman spectra of both phases resemble one another strongly and are consistent with the cotunnite-type structure. These results confirm that ZrO2 and HfO2 undergo transitions to the same phase at high pressure.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1151-2916.1997.tb03073.x
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 42
    Electronic Resource
    Electronic Resource
    A Symposium in Honor of Professor Arthur H. Heuer's 60th Birthday (1997)
    Oxford, UK : Blackwell Publishing Ltd
    Journal of the American Ceramic Society 80 (1997), S. 0 
    Details
    ISSN: 1551-2916
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1151-2916.1997.tb19967.x
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 43
    Electronic Resource
    Electronic Resource
    Effect of Shear Stress on the Atomistic Structure of a Grain Boundary in Strontium Titanate (1997)
    Oxford, UK : Blackwell Publishing Ltd
    Journal of the American Ceramic Society 80 (1997), S. 0 
    Details
    ISSN: 1551-2916
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: We have studied the atomistic structure of a σ3 (111) grain boundary in strontium titanate by high-resolution transmission electron microscopy (HRTEM). Quantitative evaluation of HRTEM images reveals that shear stresses, which may originate from processing or external loading, have an important effect on the translation state of the two adjacent grains and on the ion positions at the grain boundary. While under low shear stress the boundary exhibits mirror symmetry with respect to the boundary plane and a comparatively large free volume, high shear stress transforms the structure to a “lock-in” configuration, which has no mirror symmetry and a smaller excess volume. These results suggest that internal or external stresses may significantly alter the charge transport properties of SrTiO3.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1151-2916.1997.tb03032.x
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 44
    Electronic Resource
    Electronic Resource
    Dislocation Cores and Hardness Polarity of 4H-SiC (1997)
    Oxford, UK : Blackwell Publishing Ltd
    Journal of the American Ceramic Society 80 (1997), S. 0 
    Details
    ISSN: 1551-2916
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: The hardness of opposite basal faces of 4H-SiC single crystals has been measured in the temperature range 25°-1200°3C. A strong hardness anisotropy between the silicon-terminated (0001) and carbon-terminated (0001) faces of this polar crystal has been found. Transmission electron microscopy investigation of the dislocations in the plastic zone of the 1200°3C indentations shows that they lie predominantly on the basal planes parallel to the indented face, and the extra-half planes of the nonscrew dislocations originate from the indented face. It is also found that, when the (0001) Si-terminated face is indented, the dislocations are either widely dissociated, with the width of the stacking fault ribbon much larger than the equilibrium value, or else they are single leading partials, with the corresponding trailing partials absent. In this case, all the leading partials are found to have a silicon core. On the other hand, the dislocations in the plastic zone of the carbon-terminated face are in the form of dissociated dislocations, with the width of the associated stacking fault ribbons appreciably less than the equilibrium value. Moreover, the leading partials of éhese dissociated dislocations have a carbon core. The results indicate that the hardness of the polar basal faces of 4H-SiC at elevated temperatures is partly determined by the nature of the dislocation cores nucleated by the indentation process. It is argued that this is due to the influence of the core on the generation and glide of the leading partial dislocations.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1151-2916.1997.tb03033.x
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...