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Papers by Author: Akira Yamaguchi

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Synthesis and Properties of Al₄SiC₄ by Carbothermal Reduction

Authors: Jian Li Zhao, Chang An Wang, Akira Yamaguchi, Jia Lin Sun, Xin Sheng Zhang

Abstract: Al4SiC4 is probably used as non-oxide raw material for high-temperature ceramics. Al4SiC4 was synthesized by using starting materials of metal-carbon, metal-oxide- carbon or carbides. In this paper, Al4SiC4 has been synthesized by using oxides (Al2O3 and SiO2) and carbon as starting materials through carbothermal reduction process. The oxidation properties in air and O2 atmosphere by TG method and the stability of the synthesized Al4SiC4 heated in moisture were investigated. Pure Al4SiC4 phase was synthesized when heating the mixture powder of Al2O3, SiO2 and C (C : Al2O3 : SiO2 = 8 : 2 : 0.8, in molar ratio) at 1700°C for 8h in flowing Ar atmosphere. The synthesized Al4SiC4 powder consists of platelet shape grains with size of 68μm length, 35μm width and 1μm thickness. Al4SiC4 obviously oxidized from 800°C when heated in flowing air or O2 atmosphere. When keeping Al4SiC4 powder in moisture, it was not observed to be reacted with water by XRD and SEM analysis.

Investigation into Hydration Resistance of CaO-Containing Materials

Authors: Wei Lin, Jian Li Zhao, Junji Ommyoji, Akira Yamaguchi

Abstract: In order to develop an ideal material for the nozzle used in steel continuous casting process, the hydration resistance of some CaO-containing complex oxides and CaO-NiO solid solutions were investigated systematically. The hydration resistance of the complex oxides was CT >CZ>CS>CF>CB3BTB2 B>CB2BS>>CB2BF>CB3BA>CAB2B>CaO. CT should be a promising material for the nozzle. A large number of fine secondary-NiOss particles were separated from the CaOss crystal grains in CaO-NiO solid solution and improved the hydration resistance.

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Sintering and Characterization of Zr₂Al₃C₅ Monolith

Authors: Uraiwan Leela-adisorn, Seong Min Choi, Shinobu Hashimoto, Sawao Honda, Hideo Awaji, K. Hayakawa, Akira Yamaguchi

Abstract: Zr2Al3C5 has been successfully synthesized via solid state reaction between Al, ZrC and carbon powder at 1600 in vacuum. This complex carbide has very strong bond between metal atoms and carbon atoms. Thus, this material has a potential to be utilized as structural materials. Some properties of Zr2Al3C5 powder from solid-state reaction in vacuum had been tested. It was found that this powder was completely oxidized in air at 900 1 h, and can be hydrated in moist air. These drawbacks might come from the high reactivity of the powder due to synthesis in vacuum. Zr2Al3C5 powder from solid state reaction in vacuum was sintered at various temperatures from 1500 to 2000 under vacuum with pulse electric current sintering (PECS) and pressureless sintering. Zr2Al3C5 started to sinter at 1500 and got partially dense from 1700. Physical properties and mechanical properties of this material were investigated and discussed.