Investigation of the effect of pressure, sintering temperature and time on silicon carbide microstructure

Abstract

In this research, SiC ceramics were densified via spark plasma sintering (SPS) with 0.5wt.% B4C and 1.5wt.% C additions at temperatures ranging from 1900 to 2000°C for 5-65min under 10-50MPa applied pressure with an intermediate dwell at 1400°C, and the effects of applied pressure, sintering temperature, and dwelling time were examined. The samples sintered under 50MPa applied pressure had high density (>99%), and showed high elastic modulus (~420MPa). However, lower applied pressure caused a decrease in density and elastic properties. The increase of sintering temperature from 1900 to 2000°C, while sintering time and pressure remained the same, caused grains coarsening. Increasing the dwelling time for the samples sintered at 1900 and 2000°C showed that sintering at a relatively lower temperature for a longer period of time did not increase grain size significantly. On the other hand, increasing the dwelling time at 2000°C caused excessive grain growth. The results show that fine-grained highly dense SiC can be produced by spark plasma sintering at 1900°C for 5min under 50MPa.

Keywords

• silicon carbide
• spark plasma sintering
• pressure
• sintering temperature
• sintering time