Synthesis of highly dense Ti3SiC2 by HIP and its characterization
Gao Ning Feng; Miyamoto Yoshinari; Tanihata Kimiaki
Abstract:The pure and dense Ti3SiC2 material was tried to fabricate by two different approaches; HIP sintering of the SHS derived Ti3SiC2 powders, and the reactive HIP sintering of the mixed powders of Ti, SiC, and C. The product with the highest content of Ti3SiC2 consisted of 97.vol% Ti3SiC2 and the remaining TiCx. This material was obtained by the reactive HIP, carried out at 1500 deg., 40MPa for 30 min. The density was 99% of theoretical. The Ti3SiC2 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, 11.2MPam1/2, 410MPa, respectively. These mechanical properties are considered to be almost the intrinsic property of the bulk Ti3SiC2. The severe oxidation of the Ti3SiC2 started at about 1100 degree. The electrical resistivity was 1.77x10-6 Wm at room temperature. It increased with increasing temperature, but showed the discontinuous change at around 1030 - 1040K. The Seebeck coefficient was 4 - 20 mV/K in the range from 300K to 1200K. This small positive value suggests that the Ti3SiC2 is a semimetal with hole carriers. Key Words:Ti3SiC2, HIP, SHS, Vickers hardness, Ypung's modulus, fracture toughness, flexural strength, thermoelectric power, semimetal