Microstructural development during spark plasma sintering of ZrB2-SiC-Ti composite

The present study investigates the effect of Ti addition on the microstructure development and phase evolution during spark plasma sintering of ZrB2-SiC ceramic composite. A ZrB2-20 vol% SiC sample with 15 wt% Ti was prepared by high-energy milling and spark plasma sintering at 2000 degrees C for 7 min under 50 MPa. The X-ray diffraction test, microstructural studies and thermodynamic assessments indicated the in-situ formation of several compounds due to the chemical reactions of Ti with ZrB2 and SiC. The Ti additive was completely consumed during the sintering process and converted to the ceramic compounds of TiC, TiB and TiSi2. In addition, another refractory phase of ZrC was also formed as a result of sidelong reaction of ZrB2 and SiC with the Ti additive.