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  • 1
    Electronic Resource
    Electronic Resource
    Interface reactions between manganese zinc ferrite single crystals and SiO2-PbO-ZnO ternary systems (1995)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 78 (1995), S. 7045-7052 
    Details
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Interface reactions between Mn-Zn ferrite single crystals and SiO2-PbO-ZnO ternary systems were investigated using scanning electron microscope, electron probe microanalyzer, and x-ray diffractometer. The addition of ZnO in a SiO2-PbO glass resulted in inhibition of formation of the intermediate phase and suppression of dissolution of the ferrite. The interface morphology became a dendrite structure with increase of ZnO concentration in the glass. Appearance of the anomalous concentration profile of Zn and Mn at the ferrite adjacent to the interface was investigated in terms of the dissolved quantity of Mn and Zn ion. It was found that Zn ion has dissolved from the ferrite into the glass melt during the reaction and Mn ion in the ferrite dissolved into the glass melt more than Zn ion, resulting in changing the undissolved ferrite adjacent to the interface into a Zn-rich Mn-Zn ferrite, Mn0.16Zn0.85Fe2O4, after reaction with 57SiO2-38PbO-5ZnO (in mol %) glass. It was considered that the source of the hump of Zn concentration at the ferrite adjacent to the interface would be the undissolved, remaining Zn ions. A microscopic model was suggested. © 1995 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.360408
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  • 2
    Electronic Resource
    Electronic Resource
    Solvothermal Synthesis of Tungsten Oxide Nanorod/Nanowire/Nanosheet (2005)
    Oxford, UK : Blackwell Science Inc
    Journal of the American Ceramic Society 88 (2005), 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 simple process enables to synthesize tungsten oxide with various nanomorphologies, i.e. nanorods, nanowires, and nanosheets. The tungsten hexachloride (WCl6) was used as a raw material and the tungsten oxide nanoparticles were obtained by solvothermal treatment with solvents, i.e., ethanol, mixed solvent (ethanol+water), and water, at 200°C for 10 h. The various crystalline phases of tungsten oxide, such as monoclinic W18O49 nanorods, hexagonal WO3 platelets, and monoclinic WO3 nanosheets, were synthesized by simply changing the composition of the solvent. The oxygen, which was contained in water, played an important role in the final tungsten oxide phase. Especially, W18O49 nanorods grew to nanowires as the concentration of WCl6 was decreased. Using this simple process, it will be possible to control the crystalline phase and morphologies of nanostructured tungsten oxide system.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1551-2916.2005.00341.x
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  • 3
    Electronic Resource
    Electronic Resource
    Cyclic Fatigue–Crack Propagation Behavior in Silicon Carbide: Long- and Small-Crack Behavior (2001)
    Westerville, Ohio : American Ceramics Society
    Journal of the American Ceramic Society 84 (2001), 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: Cyclic fatigue properties of high-toughness SiC with additives of Al2O3 and Y2O3 were examined, with a focus on differences between long- (〉3 mm) and small-crack (〈200 μm) behavior. Small cracks were initiated with Vickers indents placed on the tensile surfaces of beams, and crack extension was monitored optically under cyclic load. For small cracks, high growth rates which exhibited a negative dependence on the far-field driving force were observed. Such behavior was explained by both indent-induced residual stresses and the relative size of cracks compared with bridging zone lengths.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1151-2916.2001.tb00696.x
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  • 4
    Electronic Resource
    Electronic Resource
    Effect of Silica Surface Dopants on the Formation of Alumina/Aluminum Composites by the Directed Metal Oxidation of an Aluminum Alloy (2001)
    Westerville, Ohio : American Ceramics Society
    Journal of the American Ceramic Society 84 (2001), 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: This study focused on clarifying the effect of SiO2 surface dopants on the formation of Al2O3/aluminum composites, especially on oxidation phenomena during the incubation period. The present results showed that a surface dopant decreased the incubation period of an Al-Mg-Si alloy, as well as that of an Al-Mg alloy, and that addition of an external surface dopant decreased the incubation period more effectively than did an internal alloying of silicon. A two-step oxidation process was also conducted. In the first step of the process, an aluminum alloy was oxidized without a surface dopant and cooled to room temperature during the incubation stage. In the second step, the same specimen was surface-doped with SiO2 powder and reoxidized. The incubation time for the specimen subjected to the two-step oxidation process was the same as that for the single-step specimen oxidized with a surface dopant. The substantial decrease in the incubation period, especially for the Al-Mg alloy, is ascribed to interaction between the SiO2 surface dopant and the MgO layer. This interaction made the MgO layer thinner and increased the number of magnesium vacancies in the MgO layer, thus providing an appropriate microstructure in the MgO layer for bulk-growth initiation.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1151-2916.2001.tb01047.x
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  • 5
    Electronic Resource
    Electronic Resource
    Effect of Tangential Loading on Critical Conditions for Radial Cracking in Brittle Coatings (2001)
    Westerville, Ohio : American Ceramics Society
    Journal of the American Ceramic Society 84 (2001), 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: Results of Hertzian contact tests investigating the effects of superposed tangential loads on the critical conditions for radial cracking at the undersurfaces of brittle coatings on compliant substrates are reported. It is demonstrated that these effects are secondary, so that conventional normal indentation remains an appropriate test procedure for characterizing this highly deleterious mode of coating fracture under a wide range of complex loading conditions.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1151-2916.2001.tb01081.x
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  • 6
    Electronic Resource
    Electronic Resource
    Pyrolytic Conversion of Spherical Organo-silica Powder to Silicon Nitride under Nitrogen (1998)
    Westerville, Ohio : American Ceramics Society
    Journal of the American Ceramic Society 81 (1998), 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: Monodisperse, spherical Si3N4 powder composed of fine particulates was synthesized by pyrolyzing spherical organo-silica powder under nitrogen. The organo-silica powder was prepared by hydrolyzing a mixture of phenyltrimethoxysilane (PTMS) and tetraethoxysilane (TEOS) in a methanol solution of water and ammonia. The organo-silica powder consisted of 81.3 at.% silicon units derived from PTMS and 18.7 at.% silicon units derived from TEOS. During the pyrolysis under nitrogen, the organo-silica powder decomposed to a mixture of free carbon and silica, with an increase of the surface area, at 500°-600°C, followed by the formation of alpha-Si3N4, with ß-Si3N4 as a minor phase, at 1450° and 1500°C and ß-SiC at 1550°C. The pyrolyzed powders, which retained the spherical shape and monodispersity of the organo-silica powders, with a reduction in mean particle diameter, were composed of fine particulates that were ~40 nm in size.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1151-2916.1998.tb02624.x
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  • 7
    Electronic Resource
    Electronic Resource
    Formation and Characterization of Monodisperse, Spherical Organo-Silica Powders from Organo-Alkoxysilane-Water System (1998)
    Westerville, Ohio : American Ceramics Society
    Journal of the American Ceramic Society 81 (1998), 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: Monodisperse, spherical organo-silica powders were synthesized from an immiscible mixture of an aqueous NH4OH solution and organo-alkoxysilanes, such as phenyl-trimethoxysilane (PTMS), methyltrimethoxysilane (MTMS), and methyltriethoxysilane (MTES). When the organo-alkoxysilanes were added to the aqueous NH4OH solution with stirring, organo-alkoxysilane/water macroemulsions were formed because of the immiscibility of the aqueous NH4OH solution and the organo-alkoxysilane. In the emulsion, organo-alkoxysilane droplets dissolved into the water phase through the droplet-water interface, and the organo-silica powder was formed by the hydrolysis and condensation of the organo-alkoxysilane. The powders were obtained reproducibly under broad concentrations of organo-alkoxysilanes; 0.3-1.5 mol/L for PTMS, 0.3-0.6 mol/L for MTMS, and MTES, with concentrations of ammonia between 0.0625 and 2.0 mol/L. According to the analysis of the solid-state MAS 29Si NMR and the 13C NMR analysis, the organo-silica powder did not contain any residual alkoxy groups, only carbon sources from nonhydrolyzable R groups: phenyl groups in PTMS, and methyl groups in MTMS and MTES.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1151-2916.1998.tb02466.x
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  • 8
    Electronic Resource
    Electronic Resource
    Hydrothermal Synthesis of Spherical Perovskite Oxide Powders Using Spherical Gel Powders (1998)
    Westerville, Ohio : American Ceramics Society
    Journal of the American Ceramic Society 81 (1998), 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 perovskite oxide powders, composed of fine particulates, were prepared by using spherical gel powders under hydrothermal conditions. Spherical PbTiO3, BaTiO3, and SrTiO3 powders were synthesized from spherical TiO2 gel powders, and spherical PbZrO3 powder from spherical ZrO2 gel powder. Spherical Pb(Zr0.5, Ti0.5)O3 and Ba(Zr0.5,Ti0.5)O3 powders were prepared from spherical ZrTiO4 gel powders. Lead acetate trihydrate, barium hydroxide octahydrate, and strontium hydroxide octahydrate were used as the sources of A-site ions in each perovskite oxide (ABO3). The spherical TiO2 and ZrO2 gel powders were prepared by thermal hydrolysis of titanium tetrachloride and zirconium oxychloride, respectively, and spherical ZrTiO4 gel powder by thermal hydrolysis of a mixture of them in alcohol-water mixed solvent. During the hydrothermal treatment, the spherical gel powders retained their spherical shape to produce spherical perovskite oxide powders, composed of nanometer-sized particulates.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1151-2916.1998.tb02490.x
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  • 9
    Electronic Resource
    Electronic Resource
    Photocatalytic Activity of Monodispersed Spherical TiO2 Particles with Different Crystallization Routes (2003)
    Westerville, Ohio : American Ceramics Society
    Journal of the American Ceramic Society 86 (2003), 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: Monodispersed spherical TiO2 particles were prepared by hydrothermal crystallization and/or calcination of spherical amorphous particles, synthesized by thermal hydrolysis of TiCl4. The crystallized spherical particles were secondary agglomerates of primary nanocrystallites. Different crystallization routes and conditions provided the spherical TiO2 particles with wide particle characteristics, such as the fraction of crystallization, the size and shape of the primary nanocrystallites, and the specific surface area. The photocatalytic activity showed complex dependence on the crystallization routes and conditions. The complex dependence behavior could be explained by combining the effects of the fraction of crystallization, the specific surface area, and the adsorption ability for hydroxyl ions. Especially, in the present study, the hydrothermally crystallized TiO2 particles with large primary nanocrystallites showed the highest photocatalytic activity. The high photocatalytic activity mainly resulted from the high surface adsorption ability for hydroxyl ions, which was closely related to the well-developed (flat and faceted) morphology of primary nanocrystallite.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1151-2916.2003.tb03437.x
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  • 10
    Electronic Resource
    Electronic Resource
    Rate Effects in Critical Loads for Radial Cracking in Ceramic Coatings (2002)
    Westerville, Ohio : American Ceramics Society
    Journal of the American Ceramic Society 85 (2002), 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: Rate effects in the Hertzian contact loading of model glass/polycarbonate and silicon/polycarbonate bilayers bonded by epoxy adhesive are examined. Glass is used because of its high susceptibility to slow crack growth, making this conventional contribution to the rate dependencies easy to distinguish. Silicon is used as a control material with effectively no slow crack growth. Abrasion damage is introduced into the undersurfaces of the brittle coating layers to provide controlled flaws for the initiation of radial cracks from flexural stresses introduced by the contact loading. Critical loads are measured as a function of loading rate. Comparative flexural strength tests on free-standing abraded specimens show a pronounced rate dependence in the glass but none in the silicon, entirely consistent with slow crack growth effects. The glass/polycarbonate bilayer critical load data show a similar trend, but with stronger loading-rate dependence, suggesting an extraneous contribution to the kinetics from the adhesive/substrate. The silicon/polycarbonate bilayer data also show a loading-rate dependence, albeit much smaller, confirming this last conclusion. Data from cyclic contact tests on the glass/polycarbonate bilayers coincide with the loading-rate data on lifetime plots, eliminating the likelihood of a mechanical component in the fatigue response. It is concluded that the adhesive/substrate contribution is viscoelastic in nature, from energy-dissipating (but noncumulative) anelastic deformation during the cyclic loading. Critical load tests on bilayers with different exposures to external water show no influence of external environment, suggesting that internal moisture is responsible for the slow crack growth in the glass-coating bilayers.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1151-2916.2002.tb00398.x
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