Polycarbosilane-derived Ti3SiC2 and its reaction mechanism

IF 5.8 2区 材料科学 Q2 CHEMISTRY, PHYSICAL
Leyao Xiong, Gaoming Mo, Ke Chen, Qing Huang
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引用次数: 0

Abstract

Ti3SiC2 is a representative MAX phase that uniquely combines the merits of metals and ceramics. However, polymer-derived Ti3SiC2 has been less extensively studied, especially in terms of its reaction mechanism and structural evolution. In this study, Ti3SiC2 is synthesized by pressureless pyrolysis of PCS and TiH2, the structural evolution and chemical reactions occurring during the organic-inorganic conversion and synthesis process are investigated. The results show that Ti3SiC2 with a mass fraction of 79.2 % can be achieved by pressureless pyrolysis of PCS and TiH2 powders, with a Ti-to-Si atomic ratio of 3:1.7, at 1350 ℃. The presence of TiH2 enhances the ceramic yield of PCS at 1000 ℃ compared to pure PCS, as some branched and crosslinking structures form between 100 ℃ and 300 ℃. By 800 ℃, the organic-inorganic conversion of PCS and the decomposition of TiH2 are complete, resulting in the formation of amorphous SiC, free C and porous Ti. Concurrently, some SiC may transform into amorphous Si and C in the presence of porous Ti. At 1000 ℃, T5Si3 forms within the porous Ti matrix, while TiC is generated on the periphery. Between 1200℃ and 1350 ℃, a reaction between these two phases and free C leads to the synthesis of Ti3SiC2. The formed Ti3SiC2 phase begins to decompose at 1450 ℃ and completely breaks down into TiC, SiC, and TiSi2 at 1600 ℃.
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来源期刊
Journal of Alloys and Compounds
Journal of Alloys and Compounds 工程技术-材料科学:综合
CiteScore
11.10
自引率
14.50%
发文量
5146
审稿时长
67 days
期刊介绍: The Journal of Alloys and Compounds is intended to serve as an international medium for the publication of work on solid materials comprising compounds as well as alloys. Its great strength lies in the diversity of discipline which it encompasses, drawing together results from materials science, solid-state chemistry and physics.
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