A new strategy to obtain thin ZrO2–Al2O3 composite aerogel coating with prominent high–temperature resistance and rapid heat dissipation

High–temperature resistant aerogel coating usually prevents damage to walls and equipment in a harsh high–temperature environment, but these coating still has some disadvantages in practical application, such as short time of high–temperature resistance or low stability. In this work, ZrO2–Al2O3 composite aerogel coating with prominent high–temperature resistance and rapid heat dissipation was successfully fabricated by employing (Al(H2PO4)3, AHP) as high–temperature adhesive to form stable phosphates products. The thermal conductivity and thermal diffusivity of the obtained ZrO2–Al2O3 composite aerogel coating are 0.1602–0.1623 ​W/mK and 0.3488–0.4702 ​mm2/s, respectively. The resultant aerogel coating with a thickness of 1.4 ​cm showed good performance in heat resistance with tolerance of flame up to ∼1300oC for 15 ​min, and rapid heat dissipation that can be cooled to 32.7–38.4oC within 60–70 ​s. Phosphate products, such as AlPO4 and ZrP2O7, are mainly formed at high temperature with the introduction of AHP, which fundamentally improves the high–temperature resistance and flame retardant of aerogel coating. Different microstructure and pore structure are responsible for the heat dissipation performance of the aerogel coating, which shows high thermal diffusivity of 0.3488–0.4702 ​mm2/s. Overall, this work provides a new strategy for preparing aerogel coating with high–temperature resistance, flame retardant, thermal stability and rapid heat dissipation suitable for harsh conditions.