アルミナ-窒化ケイ素ウイスカー複合体の焼結と諸特性

概要

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Composite ceramics of α-alumina mixed with up to 40 vol% β-silicon nitride whisker were fabricated by hot-pressing at 1400°-1700℃ under 30 MPa for 30 min. The properties (bending strength, fracture toughness, thermal shock resistance, and oxidation resistance et al.) of the hot-pressed bodies were investigated. Dense alumina-Si_3N_4 whisker composite ceramics were obtained in the region of whisker contents up to 30 vol% at the sintering temperatures above 1600℃. The composite mixed with 20 vol% Whisker and fired at 1600℃ showed the highest bending strength (about 610 MPa) , which is lower than the maximum strength of alumina (about 630 MPa). These composites had more excellent high temperature strength, hardness and thermal shock resistance than Monolithic alumina. The fracture toughness (about 4.7 MPa・m^<l/2>) of a composite with a whisker content of 30 vol% was 1.7 times as large as that of monolithic alumina. The weight gain by oxidation at 1400℃ increased with increasing oxidation time and whisker content, but decrease in strength was not observed after oxidation.
社団法人日本セラミックス協会の論文
1991-05-01