High-temperature-resistant ZrO₂ coating with SiC-whisker-enhanced interfacial bonding strength and improved emissivity for flexible silica fibre fabric

As a critical structure of thermal protection systems, flexible fibre insulation felts are widely used on the leeward surface of spacecrafts. To enhance the thermal resistance of flexible fibre felts, SiC_w-ZrO₂ coatings with different SiC whisker (SiC_w) contents were fabricated on the surface of a high-silica-fibre fabric (HSFF) by employing a sol-gel method combined with a spraying route. The introduction of SiC_w having a length of 10–50 μm effectively improved the coating integrity. After calcination at 1000 °C for 1 h, the SiC_w-ZrO₂ coating containing 8 wt% SiC_w did not damage the tensile strength and flexibility of the fibre fabric, and the interfacial bonding strength between the coating and HSFF reached 0.40 MPa, benefitting from the whisker toughening mechanism. The SiC_w-ZrO₂ coating with a high emissivity of 0.96 in the 2–14 μm wavelength range reduced the surface temperature of the flexible insulation felt by approximately 300 °C when a butane torch was applied at above 1300 °C.