Microstructure and ablative properties of Si-SiC coating prepared by spark plasma sintering

In order to improve ablation resistance of graphite, Si-SiC coatings were fabricated on the graphite substrate by spark plasma sintering. Effects of the sintering temperature and composition were investigated on the microstructure and ablation resistance of the coatings. Phase synthesis and microstructure were studied by X-ray diffraction and field emission scanning electron microscope, respectively. SiC was successfully in-situ synthesized by SPS of Si-SiC-Al2O3 powders mixture. The results of ablation test showed that the ablation resistance of the graphite was remarkably enhanced and the sample with 30 wt% Si had the optimum properties which was sintered at 1400 degrees C. In contrast to uncoated graphite, the ablated mass and the mass ablation rate of the sample with the composition of 30Si-60SiC-10Al(2)O(3) (wt%) decreased by 84.7% and 87.5%, respectively.