実験及び計算機による窒化アルミニウム複合焼結体での粒成長と微構造についての検討

概要

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Grain growth of AIN-TiN composite ceramics was studied under conditions where the AIN/Al_2O_3/Y_2O_3 grain boundary phase is presumed to be liquid. It was found that the growth of AIN grains was strongly inhibited as the level of TiN additions increased. Compared to AIN, TiN particles showed very little grain growth under the condition studied. AIN grain growth in both monolithic and composite systems proceeded at a rate of one-third the sintering time, and it was postulated that AIN grain growth proceeded by the "solution-reprecipitation" mechanism. Microstructure observation showed that TiN particles were present at grain boundaries and within AIN grains. Heat treatment of the composite resulted in a severe microstructural change in which the grain boundary phase was isolated at triple points of AINg rains. Computational studies of grain growth in the presence of both, a liquid phase and dispersoids, similar to the AIN-TiN composite system, were under taken using Monte Carlo simulation based on the Potts model. The simulation effectively expressed the dependency of grain growth on the size and amount of dispersoid as well as predicting the inclusion of dispersoid particles into matrix grains. Adjusting the γ_sl/γss value from 0.5 to 1.0 yielded microstructural changes that were similar to those observed upon annealing experiments.
社団法人日本セラミックス協会の論文
2001-04-01