Spark Plasma Sintering of SiC: Influence of TiC Additive

Abstract

The compaction kinetics, phase composition and mechanical characteristics of pure SiC and pure TiC ceramics, as well as SiC–TiC composite ceramics, obtained by spark plasma sintering (SPS), were studied depending on the component content and SPS-modes. It was found that at a fixed pressing pressure (P_SPS = 45 MPa) in a given range of temperatures and sintering times (1800 ≤ T_SPS ≤ 2000°C and 0 min ≤ t_SPS ≤ 10 min), the relative density of sintered ceramics increases with increasing temperature and sintering time and reaches maximum values of 88, 99.9, and 96.2 of the calculated value for SiC, TiC, and SiC + TiC(10 wt %), respectively. It is shown that sintering of composite ceramics in the SiC–TiC system occurs through the formation and subsequent high-temperature decomposition of intermediate phases of binary carbides. It is demonstrated that the microhardness of SiC–TiC composite samples is determined as an additive value between the hardnesses of the included phases SiC (HV = 2948 ± 238 N/mm²) and TiC (HV = 2465 ± 256 N/mm²).