アルミナの微細組織におけるナノ粒径SiCとミクロ粒径YAG粒子分散の影響

概要

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Alumina-based ceramic composites prepared by particulate dispersion using SiC and Y_2O_3 as additives were studied under hot-pressing at 1400 to 1600℃ for 0 to 20h. An yttrium aluminum garnet(YAG, Y_3Al_5O_<12>)phase was formed by the reaction between Al_2O_3 and Y_2O_3 above at 1400℃ after 10 min of hot-pressing, and dense Al_2O_3/5 vol%SiC/20 vol%YAG composites resulted. The YAG phase was dispersed at the grain boundary of the Al_2O_3 matrix with equiaxed grains. Fine SiC was dispersed uniformly within the Al_2O_3 matrix, whereas coarse SiC particulates, which showed stacking faults, were located in the grain boundaries between the Al_2O_3 and YAG. The YAG phase was bonded directly to the Al_2O_3. An impurity phase, which apparently was amorphous, could be detected at the interface between the Al_2O_3 and SiC. The grain size of the monolithic Al_2O_3 increased remarkably with increases in hot-pressing temperature and time ; grain growth in the Al_2O_3/SiC/YAG composites were effectively restrained, and those samples exhibited a narrower grain size distribution. This uniformly fine microstructure could be attributed to the incorporation of the YAG and SiC particulates, because of grain boundary pinning by the particulates.
社団法人日本セラミックス協会の論文
1998-02-01