水中衝撃圧力によるSiCウイスカー強化窒化ケイ素複合材の作製と二,三の性質

概要

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SiC whisker-reinforced Si_3N_4-based composites without additives were compacted by underwater-shock wave. The composites contained 10, 20 and 30 vol% SiC whisker as reinforcements. There were no macrocracks in all shock compacted composites. The as-compacted and specimens sintered at various temperatures for 5h were characterized by the measurements of relative density, micro Vickers hardness and fracture toughness. The relative density of a sintered Si_3N_4-10 vol% SiC whisker composite was higher than that of sintered Si_3N_4-20 and 30 vol% SiC whisker composites, and reached the theoretical density by sintering at 1973 K. Hardness of each composite increased up to 1823 K in proportion to sintering temperature, and then saturated above 1823 K. The hardness and fracture toughness of the Si3_N_4-30 vol% SiC whisker composite sintered at 1973 K were about 29 GPa and 5.0 MPa √<m>, respectively. The fracture toughness was 25% higher than those of monolithic Si_3N_4 and other obtained composites sintered at the same temperature. SEM observation showed that whisker bridging and deflection were observed in sintered composites and that the matrix of the Si_3N_4-30 vol% SiC whisker composite consisted of plate-like and submicron order fine needle-like β-Si_3N_4 grains.
社団法人日本セラミックス協会の論文
1993-04-01