Dense Ti3SiC2 prepared by reactive HIP

The dense polycrystalline Ti3SiC2 has been synthesized by reactive HIPing o f Ti, SiC and C powders. The bulk material with the highest Ti3SiC2 content about 97 vol % was obtained when treated at 1500 degrees C, 40 MPa for 30 min. The density was 99% of the theoretical value. The Ti3SiC2 grains had t he columnar and plate-like shapes. The grains were well boned to form a net work structure. Many stacking faults were observed along the (001) plane of Ti3SiC2. The Vickers hardness, Young's modulus, flexural strength and frac ture toughness were 4 GPa, 283 GPa, 410 MPa and 11.2 MPa m(1/2), respective ly. The Ti3SiC2 was stable up to 1100 degrees C in air. The electrical resi stivity was 2.7 x 10(-7) Omega . m at room temperature. The resistivity inc reased linearly with the increasing temperature. It may be attributed to a second order phase transition. The Seebeck coefficient was from 4 to 20 mu V/K in the temperature range 300-1200 K. It seems that Ti3SiC2 is semi-meta llic with hole carriers from this small positive value. (C) 1999 Kluwer Aca demic Publishers.