酸窒化アルミニウム(γ-AION)の作製と特性

概要

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The preparation of the γ-AI0N ceramics has been carried out by a reaction sintering process. Mixed powder compacts consisting of Al_2O_3 and AIN were heated in N_2. The lattice parameters of the γ-AION, which were obtained from the compacts by heating at 1850℃ for 2h, linearly changed from 0.7939 to 0.7953 nm for the composition range from 68 to 78 mol% Al_2O_3 in the starting mixture. Dense γ-AI0N ceramics were obtained by sintering the compact with Y_2O_3, however their bending strength was lower than that of specimens without Y_2O_3. γ-AI0N ceramics with various N/O ratio, prepared from 0.25 mass% Y_2O_3-containing compacts with various ratio of Al_2O_3 and AIN, were characterized with respect to their mechanical properties. Young's modulus increased slightly with increase of N/O ratio. There lation between N/O ratio and bending strength, Vickers hardness and thermal expansion coefficient were of difficult interpretation. The oxidation behavior of γ-AI0N ceramics in air was also investigated. γ-AI0N ceramics were little oxidized below 1200℃. At 1300℃, the oxidation of γ-AI0N ceramics was accelerated, because the cracks along the surface occurred in the oxidized layer.
2001-04-01