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Situ Reaction (situ + reaction)
Selected AbstractsMicrostructures and Mechanical Properties of ZrC Reinforced (Zr-Ti)-Al-Ni-Cu Glassy Composites by an In Situ Reaction,ADVANCED ENGINEERING MATERIALS, Issue 5 2009Tao Liu Wetting behaviors of TiC and ZrC by a molten Zr55Al10Ni5Cu30 alloy were investigated in order to give an instruction in synthesizing the glassy composites using a liquid casting route. The (Zr-Ti)55Al10Ni5Cu30 bulk metallic glass matrix composites, reinforced by in situ ZrC particles were then fabricated by copper mold casting. The microstructure and mechanical properties were investigated systematically. [source] Fabrication of High-Purity Ti3SiC2 Powders by an In Situ Reaction of Polycarbosilane and Metal TitaniumJOURNAL OF THE AMERICAN CERAMIC SOCIETY, Issue 8 2010Jinshan Yang High-purity titanium silicon carbide powders were fabricated by an in situ reaction of polycarbosilane and metal titanium. The effects of the starting reagents and the pyrolysis temperature on the fabrication of high-purity Ti3SiC2 were studied. The results showed that high-purity Ti3SiC2 could be obtained when the atomic ratio of Ti:Si was 3:1.5 and the effect of the temperature of pyrolysis on the purity of the powders was insignificant. The atomic ratio of Ti:Si was calculated on the basis of the empirical formula of SiC2.5H7. [source] ZrW2O8,ZrO2 Continuous Functionally Graded Materials Fabricated by In Situ Reaction of ZrO2 and WO3JOURNAL OF THE AMERICAN CERAMIC SOCIETY, Issue 3 2010Li Sun ZrO2 powder and ZrO2+WO3 powder mixture were stacked, cocompacted, and cosintered in a cylindrical die, the processing steps commonly used to fabricate multilayer materials. The soak duration and the mass ratio among layers in the processing have been varied to yield a wide range of final sintered samples. At appropriate soak durations, the sintered samples resulted in continuous functionally graded materials (FGMs) made of ZrW2O8 and ZrO2. In other words, instead of the expected discrete, multiple-layered materials, the resulting samples are characterized by the axially, continuously varying physical properties. The continuous FGM structure is formed by several mechanisms: the balance between the reaction of ZrO2 and WO3 and the decomposition of ZrW2O8, as well as the sublimation and diffusion of WO3. The continuous FGMs can be utilized to reduce the thermal stress induced from a thermal gradient loading within a material system. This study shows that the processing steps typically used for multilayer FGMs can also be used to create continuous FGMs for some special material combinations. [source] Microwave Hybrid Post-Heat Treatment of Reaction Sintered Alumina/Lanthanum Hexaaluminate Composite Ceramics,ADVANCED ENGINEERING MATERIALS, Issue 3 2010Zahra Negahdari One of the main problems in development of in situ reaction sintered alumina/lanthanum hexaaluminate composite ceramics is achievement of simultaneous densification and in situ formation of lanthanum hexaaluminate (LHA) platelets inside the matrix. Microwave hybrid post-sintering was investigated as a method to enhance the solid-state reaction of LHA formation and the densification of composite ceramics with 2.8,80 vol% LHA. Comparison of the conventionally and microwave assisted sintered alumina/lanthanum hexaaluminate composite ceramics revealed that utilization of microwave heating in second stage of sintering could enhance the solid-state reaction, the densification, and the anisotropic grain growth of the LHA platelets in ceramics containing more than 20 vol% LHA and for heat treatment at 1500,°C. [source] Fabrication of High-Purity Ti3SiC2 Powders by an In Situ Reaction of Polycarbosilane and Metal TitaniumJOURNAL OF THE AMERICAN CERAMIC SOCIETY, Issue 8 2010Jinshan Yang High-purity titanium silicon carbide powders were fabricated by an in situ reaction of polycarbosilane and metal titanium. The effects of the starting reagents and the pyrolysis temperature on the fabrication of high-purity Ti3SiC2 were studied. The results showed that high-purity Ti3SiC2 could be obtained when the atomic ratio of Ti:Si was 3:1.5 and the effect of the temperature of pyrolysis on the purity of the powders was insignificant. The atomic ratio of Ti:Si was calculated on the basis of the empirical formula of SiC2.5H7. [source] In-situ TiC precipitation in molten Fe-C and their characterisationCRYSTAL RESEARCH AND TECHNOLOGY, Issue 6 2008K. I. Parashivamurthy Abstract TiC particles were formed in liquid iron solution by the reaction between pure titanium and carbon available in molten iron. TiC particles have been precipitated in steels with four different carbon contents by in situ reactions during melting. The influence of titanium and carbon concentration on the precipitation of TiC was studied. The samples were studied by means of optical microscopy, scanning electron microscopy and X-ray microanalysis. The morphology of the obtained crystals was studied and correlated with carbon and titanium. It was found that TiC crystallises as primary crystals at 1600°C during solidification of the Fe-Ti-C melt. The obtained crystals were of cubic, rectangle and had maximum size of 18.7 µm. The size and shape of the carbides increases with increasing carbon and titanium in molten iron. (© 2008 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] Neutron Thermodiffractometry Study of Calcium Zirconate/Magnesium Oxide Formation in the ZrO2,CaO,MgO SystemJOURNAL OF THE AMERICAN CERAMIC SOCIETY, Issue 9 2004Sara Serena The reaction process to obtain CaZrO3/MgO specimens in the ZrO2,CaO,MgO system from two mixtures of natural and synthetic raw materials were analyzed by neutron thermodiffractometry; differential thermal analysis,thermogravimetry (DTA-TG) also was used. The results from the different techniques provided a complete description of the decomposition and reaction process in the samples and proved that high-temperature neutron diffraction is a powerful tool for analyzing in situ reactions up to 1250°C in both mixtures. In the present work, the evolution of the crystalline phases, the mechanism and temperature of formation of CaZrO3, and the activation energy were properly established in terms of the neutron thermodiffraction study. [source] | ||||||||||