Hot oscillatory pressing of SiC ceramics with B4C and C as sintering additives

SiC ceramics with 0.5 wt% B4C and 0.5 wt% C as sintering additives were prepared by hot oscillatory pressure (HOP) and hot pressure (HP). The mechanical properties and microstructures of the resultant ceramics were investigated. The results showed that the oscillatory pressure could effectively suppress the abnormal growth of SiC grains and promote the formation of high-density dislocation and stacking faults. The hardness of SiC ceramics made by HOP at 2000oC reached 28.9 GPa, which was much higher than that (25.9 GPa) of the sample made by HP at the same temperature. The current study suggests that HOP is a promising technique for preparing high-performance SiC ceramics.