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PREPARATION OF Mo-Si-C ULTRA-HIGH TEMPARATURE COMPOSITES.

Mo-Si-C超高温复合材料的制备。

基本信息

批准号：
07555483
负责人：
KUROKAWA Kazuya
金额：
$ 0.58万
依托单位：
HOKKAIDO UNIVERSITY
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (B)
财政年份：
1995
资助国家：
日本
起止时间：
1995 至 1996
项目状态：
已结题

项目摘要

MoSi_2, SiC and C are promising materials for ultra-high temperature applications. Therefore, combination of those materials could produce new ultra-high temperature composites. In the present study, preparations of the MoSi_2-SiC composites and the graphite-MoSi_2 joints were carried out by powder metallurgy with a spark plasma sintering equipment.MoSi_2-SiC composites : Fully dense MoSi_2-SiC composites can be produced briefly by applying a spark plasma sintering method. When mixed powders of MoSi_2 and SiC are used for the preparation of MoSi_2SiC composites, aggregation of SiC is liable to occur. On the other hand, uniform disparsion of SiC is achieved by using mixed powders of Mo, Si and C as starting materials. The reaction process and the sintering behavior of the mixed powders of Mo, Si and C were also clarified by DTA experiments and thermal expansion-shrinkage measurements during sintering. The prepared composites have outstanding oxidation resistance. In particular, it is very important finding that the composites prepared from the mixed powders of Mo, Si and C don't show simultaneous oxidation of Mo and Si even in the accelerated oxidation region. It is concluded that MoSi_2-SiC composite is a promising material for ultra-high temperature applications.MoSi_2-graphite joints : The graphite-MoSi_2 joints having high flexural strength is prepared by using a plasma sintering equipment. However, the flexural strength depends on the thickness of a SiC layr which is formed in the interfacial reaction between MoSi_2 and graphite. The formation of SiC can be suppressed completly by inserting a Ti foil between tham.

MoSi_2、SiC和C是极具应用前景的超高温材料。因此，这些材料的结合可以产生新的超高温复合材料。本研究采用火花等离子烧结设备，采用粉末冶金方法制备了MoSi_2-SiC复合材料和石墨- mosi_2接头。MoSi_2-SiC复合材料：采用火花等离子烧结的方法可以快速制备出致密的MoSi_2-SiC复合材料。用MoSi_2和SiC混合粉末制备MoSi_2SiC复合材料时，容易发生SiC的聚集。另一方面，以Mo、Si和C的混合粉末为起始原料，实现了SiC的均匀分解。通过差热分析（DTA）实验和烧结过程中的热膨胀收缩测量，阐明了Mo、Si和C混合粉末的反应过程和烧结行为。所制备的复合材料具有优异的抗氧化性能。特别值得注意的是，Mo、Si和C混合粉末制备的复合材料即使在加速氧化区也不会出现Mo和Si同时氧化的现象。结果表明，MoSi_2-SiC复合材料是一种极具应用前景的超高温材料。mosi_2 -石墨接头：采用等离子烧结设备制备了具有高抗弯强度的石墨- mosi_2接头。然而，抗弯强度取决于MoSi_2与石墨界面反应形成的SiC层的厚度。在两者之间插入钛箔可以完全抑制碳化硅的形成。