Microstructure and graphitization behavior of diamond/SiC composites fabricated by vacuum vapor reactive infiltration
来源期刊：Rare Metals2015年第6期
论文作者：Zhen-Liang Yang Li-Gen Wang Li-Min Wang Xin-Bo He Xuan-Hui Qu Rong-Jun Liu Hai-Feng Hu
文章页码：400 - 406
摘 要：To inhibit the graphitization of diamond under high temperature and low pressure, diamond/Si C composites were firstly fabricated by a rapid gaseous Si vacuum reactive infiltration process. The microstructure and graphitization behavior of diamond in the composites under various infiltration temperatures and holding time were investigated. The thermal conductivity of the resultant materials was discussed. The results show that the diamond-to-graphite transition is effectively inhibited at temperature of as high as 1600 °C under vacuum, and the substantial graphitization starts at 1700 °C. The microstructure of those ungraphitized samples is uniform and fully densified. The inhibition mechanisms of graphitization include the isolation of the catalysts from diamond by a series of protective layers, high pressure stress applied on diamond by the reaction-bonded Si C, and the moderate gas–solid reaction. For the graphitized samples, the boundary between diamond and Si C is coarse and loose.The graphitization mechanism is considered to be an initial detachment of the bilayers from the diamond surfaces, and subsequently flattening to form graphite. The ungraphitized samples present higher thermal conductivity of about 410 W·m-1·K-1due to the fine interfacial structure. For the graphitized samples, the thermal conductivity decreases significantly to 285 W·m-1·K-1as a result of high interfacial thermal resistance.
Zhen-Liang Yang1，Li-Gen Wang2，Li-Min Wang1，Xin-Bo He3，Xuan-Hui Qu3，Rong-Jun Liu4，Hai-Feng Hu4
1. Gripm Advanced Materials Co., Ltd2. State Key Laboratory of Nonferrous Metals and Processes, General Research Institute for Nonferrous Metals3. School of Materials Science and Engineering, University of Science and Technology Beijing4. College of Aerospace and Materials Engineering, National University of Defense Technology
摘 要：To inhibit the graphitization of diamond under high temperature and low pressure, diamond/Si C composites were firstly fabricated by a rapid gaseous Si vacuum reactive infiltration process. The microstructure and graphitization behavior of diamond in the composites under various infiltration temperatures and holding time were investigated. The thermal conductivity of the resultant materials was discussed. The results show that the diamond-to-graphite transition is effectively inhibited at temperature of as high as 1600 °C under vacuum, and the substantial graphitization starts at 1700 °C. The microstructure of those ungraphitized samples is uniform and fully densified. The inhibition mechanisms of graphitization include the isolation of the catalysts from diamond by a series of protective layers, high pressure stress applied on diamond by the reaction-bonded Si C, and the moderate gas–solid reaction. For the graphitized samples, the boundary between diamond and Si C is coarse and loose.The graphitization mechanism is considered to be an initial detachment of the bilayers from the diamond surfaces, and subsequently flattening to form graphite. The ungraphitized samples present higher thermal conductivity of about 410 W·m-1·K-1due to the fine interfacial structure. For the graphitized samples, the thermal conductivity decreases significantly to 285 W·m-1·K-1as a result of high interfacial thermal resistance.
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