Durability Assessment of Tile-Type Reusable Thermal Protection Materials

This study investigates the thermal performance and durability of high-emissivity-coated tile-type insulators, a key material for cost-effective and reusable thermal protection systems (TPSs), using a high-velocity oxygen fuel (HVOF) torch. A single specimen was first exposed to a heat flux of 1.25 MW/m2 for 100 s. The specimen exhibited excellent thermal performance, reaching surface temperatures exceeding 900 °C while maintaining an internal temperature increase of less than 20 °C at a depth of 40 mm from the top. Subsequently, a tile-type specimen was subjected to repeated heating at a heat flux of 0.65 MW/m2 for up to 100 s. Despite peak surface temperatures exceeding 700 °C, the internal temperature remained stable, within 50 °C, demonstrating consistent thermal protection. Furthermore, under the same heat flux conditions, the results of four repeated experiments confirmed that the temperature of the thermal protection material at a depth of 40 mm from the surface was maintained within a range of ±1.23 °C (95% confidence interval). These results demonstrate that the tile-type TPS maintains reliable thermal protection performance under repeated re-entry conditions.