Dense Ti3SiC2 prepared by reactive HIP

Abstract

The dense polycrystalline Ti₃SiC₂ has been synthesized by reactive HIPing of Ti, SiC and C powders. The bulk material with the highest Ti₃SiC₂ content about 97 vol % was obtained when treated at 1500°C, 40 MPa for 30 min. The density was 99% of the theoretical value. The Ti₃SiC₂ grains had the columnar and plate-like shapes. The grains were well boned to form a network structure. Many stacking faults were observed along the (001) plane of Ti₃SiC₂. The Vickers hardness, Young's modulus, flexural strength and fracture toughness were 4 GPa, 283 GPa, 410 MPa and 11.2 MPa m^1/2, respectively. The Ti₃SiC₂ was stable up to 1100°C in air. The electrical resistivity was 2.7 × 10⁻⁷ Ω·m at room temperature. The resistivity increased linearly with the increasing temperature. It may be attributed to a second order phase transition. The Seebeck coefficient was from 4 to 20 μV/K in the temperature range 300–1200 K. It seems that Ti₃SiC₂ is semi-metallic with hole carriers from this small positive value.