Al_2O_3-La_2O_3系からのその場反応によるアルミナ基複合材料の製造と微細構造

概要

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Al_2O_3/aluminate composites were fabricated by a solid reaction in the La_2O_3-Al_2O_3 system. The formed phase showed elongated morphology that could be controlled by varying the hot-pressing temperature and time. Dense Al_2O_3/LaAl_<11>_<18> composites were fabricated by hot-pressing above 1500℃. When the hot-pressing temperature was 1400℃, Al_2O_3/LaAlO_3 composites were formed from starting composition. The grain size of monolithic alumina ceramics increased with increasing hot-pressing temperature, and marked grain growth occurred above 1600℃. However, the elongated LaAl_<11>O_<18> phase suppressed the growth of alumina grains in the Al_2O_3/LaAl_<11>O_<18> composites. Small LaAl_<11>O_<18> grains existed in the alumina grains as an intragranular phase, while needlelike grains with a large aspect ratio existed at Al_2O_3 grain boundaries. The amount of in-situ formed LaAl_<11>O_<18> phase increased with increasing amount of La_2O_3, and the aspect ratio of LaAl_<11>O_<18> grains increased with increasing hot-pressing time.
社団法人日本セラミックス協会の論文
1998-08-01