Densitication of SiC by SPS-effects of time, temperature and pressure

Temperature, holding time and conditions of pressure application, three of the most important spark plasma sintering (SPS) parameters, have been reviewed to assess their effect on the densification and grain growth kinetics of a pure commercially available submicrometer-sized silicon carbide powder. Experiments were performed in the 1750-1850 degrees C temperature range with holding time from 1 to 10 min. Two pressure setups were used: one with pressure (75 MPa) applied at 1000 degrees C and the other with ultimate pressure applied at sintering temperature. Experimental data highlighted the fact that temperature and holding time have a different impact on grain growth and densification. Diffusion and migration mechanisms that promote grain growth were found to be strongly dependent on temperature, the latter being linked to pulsed current intensity. Conditions of pressure application suggest that the ultimate pressure applied at higher temperature increases densification by keeping small surface contact between particles. (c) 2006 Elsevier Ltd. All rights reserved.