自己燃焼高圧ホットプレス法で作製したTiC/SiC複合焼結体

概要

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Mixtures of Ti-C and Si-C powders respectively equimolar were mixed in various ratios. The final mixture was molded by using an pressure-resistant metallic mold whose inner wall was covered with a carbon felt for insulation. The molded mixture, once set in the mold, was ignited by a tungsten heater and, then, instantaneously uniaxially compressed of 1 GPa (SHS/HP processing). SEM and TEM observations were carried out to get insight in the microstructures obtained for the TiC/SiC composites. Two separated phases, namely SiC and TiC, were present in the composites prepared from Ti-C rich mixtures. In these cases, aggregates of SiC grains, often including some large pores, were found surrounded by the bulk polycrystalline TiC body. On the other hand, fine dispersions of TiC and SiC grains were obtained when nearly equimolar mixtures of Ti-C/Si-C were employed. In this latter case, a maximum value of 28 GPa for the Vickers hardness was measured.