ポリビニルシラザン由来の非晶質Si-C-Nモノリスの作製と圧縮変形(<ゲストエディターによる特集>有機-無機変換プロセス)

概要

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Consolidation of non-crystalline Si-C-N powders has been tried by hot isostatic pressing without sintering additives, in order to fabricate dense non-oxide ceramic monoliths without the crystallization. A polyvinylsilazane polymer was thermally cross-linked at 250℃ and pyrolyzed at 1050℃ under Ar atmosphere, which resulted in the formation of the ceramic state with a chemical composition of Si_<1.0>C_<1.6>N_<1.3> in atomic ratio. The pyrolyzed powders were die-pressed into rectangular bars at room temperature and consolidated by hot isostatic pressing at 1400℃-900MPa. A ceramic monolith with a level of almost full density was obtained by the consolidation, although a few pores of about 1μm still remained in the cross-sectional structure. The amorphous phase was significantly maintained in the consolidated sample. In the compression tests of the sample, only slight plastic deformation was observed at 1400℃ and 1500℃ in spite of high compressive stress over 1600MPa. On the other hand, the sample showed plastic deformation at 1600℃.
2006-06-01