Feasible Exploration Study of Anti-Silicon Element Corrosion Coating for C/C Composites

This study investigates the fabrication of a ZrSiO4-based coating (ZSO coating) on substrate surfaces using atmospheric plasma spraying (APS) technology, with ZrSiO4 as the feedstock material. A comprehensive characterization of the coating systems was conducted, including an in-depth analysis of phase composition and a systematic evaluation of the effects of spray thickness and heat treatment temperature on phase evolution, microstructural development, and the resulting properties. The coatings’ resistance to silicon corrosion and the associated failure mechanisms were thoroughly examined. The key findings reveal that the plasma-sprayed coatings form a multiphase system composed of ZrSiO4, along with the decomposition products of ZrO2 and SiO2. Optimal performance was observed within a critical thickness range of 154–240 μm. Post-deposition heat treatment at 1500 °C significantly improved the integrity of the coatings, as evidenced by a marked reduction in crack density and porosity, leading to substantial enhancement in densification. The coatings demonstrated outstanding performance in the high-temperature silicon corrosion tests, maintaining structural integrity after 4 h of exposure to molten silicon and its oxides at 1500 °C. Notably, the coatings effectively prevented the penetration of silicon into the C/C substrate, preserving strong interfacial adhesion without the formation of permeable cracks. Furthermore, post-corrosion analysis showed that the surface reaction products could be easily removed, underscoring the coatings’ exceptional protective capability for the underlying C/C substrate.