β-sialonとY_2O_3を添加したβ-sialonの破壊挙動の相違

概要

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The fracture behavior of aluminum iso propoxide der ived β sialon was investigated in comparison with com mercial β sialon sintered with Y_2O_3 by the observation of fracture surfaces. In β sialon without Y_2O_3, the mac roscopic propagation of cracks was complicated, but it resulted in transgranular fracture dominantly. On the contrary, in β sialon with Y_2O_3, the macroscopic propa gation of cracks was simple, but microscopic crack deflection and branching which occurred along the elongated grains resulted in intergranular fracture dominantly. The difference in fracture behavior be tween two sialons was originated from their micros tructure, in other words, their chemical bonds which constituted each ceramic. So, the fracture behavior of β sialon without Y_2O_3 can be distinguished from that with Y_2O_3. Thus the former is that of a typical covalently bonded ceramic and the latter is that of a composite consisting of a grain boundary glassy phase where ion ic bond would be dominant and β sialon grains. There fore, in practical applications of each ceramic, ap propriate directions for use should be chosen by con sidering the fracture behavior of each ceramic.
社団法人日本セラミックス協会の論文
1994-11-01