Mo-Si₃N₄ 系傾斜組成複合体の基礎的研究

抄録

  Dispersion of residual thermal stress by making interlayers of ceramics / metal bonding having controlled compositional gradients has been expected. Various types of the Mo-Si₃N₄ multilayers construction material with controlled compositional gradients by using particle arrangement method were made in our laboratory. Local cracks, however, were observed at the special part in reaction sintered body having controlled compositional gradients. Because, the part having around 20 vol % Mo expanded larger than other part of the body. It has been clarified by the X-ray analysis that the formation of MoSi₂ in the part of specimen containing 20 vol % Mo after sintered at 1673 K has the main effect on its expansion. To prevent this formation, the examination of sintering temperature and composition of specimen was carried out, but occurrence of cracks were not prevented. In this system of the combination, it is comparatively difficult to produce by reaction-sintering of Mo-Si₃N₄ construction material with controlled compositional gradients under author's experimental condition. By applying hotpress-sintering of the specimen added with 6 vol % of Y₂O₃ as sintering aids for Si₃N₄ in every layers, however, obtained a sintered body without any cracks.