超微粒子分散アルミナ複合焼結体の微細組織と特性に及ぼす超臨界乾燥の影響

概要

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Mixtures of 95 vol% ultrafine γ-Al_2O_3 powder and 5 vol% ultrafine SiC powder, with average particle size of 40 nm, were mixed wet-ball milling and prepared by drying their slurry with a supercritical drying method and a microwave drying method. Al_2O_3 specimens dispersed with ultrafine-SiC particles as the secondary phase were hot-pressed, their powders being prepared by both the above drying methods. Difference between the superitical drying and the microwave drying method on the microstructure of Al_2O_3/5 vol%SiC composites was investigated. Dense Al_2O_3/SiC composites were obtained at lower hot-pressing temperatures when the mixture was prepared by supercritical drying method. Influence of the drying method on the γ- to α-Al_2O_3 transition behavior was also examined. Al_2O_3/SiC powder dried by the supercritical drying method showed narrow particle size distribution and the formation of soft agglomerates. Al_2O_3/SiC composite sintered by hot-pressing the powder dried with the supercritical drying method indicated relatively higher strength, whereas the strength of Al_2O_3/SiC composite through microwave drying method was low and had the large scatter.
社団法人日本セラミックス協会の論文
1999-05-01