Effect of processing parameters on microstructure and ablation behavior of SiC/ZrB2 coating for graphite

In this research, a SiC/ZrB2 coating was produced on graphite by reactive melt infiltration and plasma spraying method. The coating characterization was performed using XRD analysis, electron microscopy equipped with energy dispersive spectrometer (EDS), and supersonic flame ablation test at 2073 K. The results indicated that the dense C/SiC coating with good ablation resistance can be obtained at 1873 K. The coating thickness decreased with increasing infiltration temperature. The results of ablation test showed that by increasing the infiltration temperature and holding time, weight loss and mass ablation rate decreased from 22.63% to 9.83% and 3.63 x 10(-3) g cm(-2) s(-1) to 1.34 x 10(-3) g cm(-2) s(-1), respectively. The results showed that by using the ZrB2 as outer coating the ablation resistance improved remarkably. The weight loss and mass ablation rates for the SiC/ZrB2 coating were 12.79% and 1.857 x 10(-3) g cm(-2) s(-1), respectively.