HIPによる高密度Ti_3SiC_2の合成と特性評価(<特集>高圧力 : 固体の高圧物性, 反応, 実験技術)

概要

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The pure and dense Ti_3SiC_2 material was tried to fabricate by two different approaches; HIP sintering of the SHS-derived Ti_3SiC_2 powders, and the reactive-HIP sintering of the mixed powders of Ti, SiC, and C. The product with the highest content of Ti_3SiC_2 consisted of 97.3vol% Ti_3SiC_2 and the remaining TiCx. This material was obtained by the reactive-HIP, carried out at 1500℃, 40MPa for 30 min. The density was 99% of theoretical. The Ti_3SiC_2 grains had columnar and plate-like shapes, which included many stacking faults along the (001) plane. The Vickers hardness, Young's modulus, fracture toughness, and flexural strength were 4GPa, 283GPa, 11.2MPa√<m> 410MPa, respectively. These mechanical properties are considered to be almost the intrinsic property of the bulk Ti_3SiC_2. The severe oxidation of the Ti_3SiC_2 started at about 1100℃. The electrical resistivity was 1.77×10^<-6>Ωm at room temperature. It increased with increasing temperature, but showed the discontinuous change at around 1030〜1040K. The Seebeck coefficient was 4〜20μV/K in the range from 300K to 1200K. This small positive value suggests that the Ti_3SiC_2 is a semimetal with hole carriers.
社団法人日本材料学会の論文
1998-10-15