β-ランタンアルミネートの分散量を変えたアルミナ基セラミックスの微構造と機械的特性

概要

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The relation between mechanical properties and the microstructure of alumina based ceramics to which LBA (LaAl_<11>O_<18>) was incorporated by in-situ reaction was examined. The dispersion of LBA and the addition of a small amount of silica produced changes in the microstructure. Even if the amount of dispersed LBA was varied, LBA was distributed uniformly in the alumina matrix. The shape of alumina changed from equiaxial to plateletlike by addition of a small amount of silica. Strength showed a maximum when the amount of dispersed LBA was 20 vol%, regardless of the presence or not of silica. The fracture toughness value was improved slightly (up to 4 MPa・m^<l/2>) for LBA dispersed specimens without silica. On the other hand, when a small amount of silica was added, the fracture toughness was improved further, reaching a maximum of 6.4 MPa・m^<l/2> for a 10 vol% of LBA. Thereafter the fracture toughness value decreased when the amount of LBA increased. The improvement in the fracture toughness of the material is attributed to the operation of mechanisms of bridging and crack deflection promoted by changes in the microstructure of the ceramic material.
社団法人日本セラミックス協会の論文
1997-08-01