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, SiCw-ZrO2 coatings with different SiC whisker (SiCw) 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 SiCw having a length of 10-50 mu m effectively improved the coating integrity. After calcination at 1000 degrees C for 1 h, the SiCw-ZrO2 coating containing 8 wt% SiCw did not damage the tensile strength and flexibility of the fibre fabric, and the interfacial bonding strength be-tween the coating and HSFF reached 0.40 MPa, benefitting from the whisker toughening mechanism. The SiCw-ZrO2 coating with a high emissivity of 0.96 in the 2-14 mu m wavelength range reduced the surface temperature of the flexible insulation felt by approximately 300 degrees C when a butane torch was applied at above 1300 degrees C.