Microstructure and ablation performance of SiC–ZrC coated C/C composites prepared by reactive melt infiltration

Abstract

To improve the ablation resistance of carbon/carbon (C/C) composites, SiC–ZrC coating was prepared by reactive melt infiltration (RMI) on C/C composites. The microstructure and morphology of the coating were characterized by scanning electron microscopy coupled with energy dispersive spectrometry (SEM–EDS), X-ray diffraction (XRD), electron probe microanalysis (EPMA) and transmission electron microscope (TEM). The TEM specimen was fabricated by focused ions beam (FIB). The results show that the SiC–ZrC coating prepared on the condition of optimum parameter exhibits outstanding anti-ablation performance. After ablation for 60 s in oxyacetylene torch environment at heat flux of 4186 kW/m2, the mass ablation rate (MAR) and linear ablation rate (LAR) of the coated composites were 1.18 × 10−3g/s and 2.47 × 10−3 mm/s, which were 83.6% and 54.5% reduction compared with uncoated composites. During the ablation, the formed molten eutectics SiO2–ZrO2 can fill the pores and act as a diffusion barrier for oxygen and heat.