The effect of Hot Isostatic Pressing on the MT sample densities

Abstract

Mechanically activated powders (0, 10, 40, 80 and 160 minutes) were formed by isostatic pressure 300 MPa to cylindrical green bodies (φ 12 mm). First set of samples was sintered at 1300°C for 30 min in air (heating rate 10 °C/min, cooling rate 5 oC/min). These samples were re-sintered at 1200 oC for 20 h in air (heating rate 20 °C/min, cooling rate 10 oC/min). Samples reached almost 90 % TD. The second set of samples was sintered at 1400 °C for 30 in air (heating rate 10 oC/min, cooling rate 5 °C/min). Relative densities increased up to 93 % TD. The samples of absence of open porosity (MTO-10, 40, 80 and 160) were post-sintered by pressure assisted technique Hot Isostatic Pressing (HIP) at 1200 °C for 2 h in argon atmosphere with pressure 200 MPa. The samples increased densities up to 96 % TD for sample MT-160. Electrical measurements were performed in the microwave field of frequency.