Preparation of ZrC/SiC composites by using polymer-derived ceramics and spark plasma sintering

ZrC/SiC composites were fabricated using Spark Plasma Sintering (SPS) combined with the Polymer-Derived Ceramics (PDC) route. The originality of this work, consisted in the direct ceramization/sintering of a ZrC/polymer mixture without any previous crosslinking steps. The presence of a polymer in our mixtures required an optimization of the thermomechanical parameters of SPS in order to promote the polymer-to-ceramic conversion prior to the densification. The optimized SPS conditions were composed of a dwell temperature of 700 degrees C for 10 min followed by a soaking temperature of 1700 degrees C for 5 min under an applied load of 75 MPa. A fine and homogenous phase distribution was achieved at relatively low temperature (1700 degrees C) compared to the high temperatures required for the sintering of the refractory composite. The influence of the addition of SiC (up to 10 wt%) was also studied and related to the final relative densities and mechanical properties of the composites.