Thermal insulation board materials are divided into two categories: porous materials and heat-reflective materials. The former uses the pores contained in the material itself to insulate heat, because the thermal conductivity of air or inert gases in the voids is very low, such as foam materials, fiber materials, etc.; The latter material has a high reflectivity and can reflect heat, such as gold, silver, nickel, aluminum foil or metallized polyester, polyimide film, etc. The aerospace industry has strict requirements for the weight and volume of the thermal insulation materials used, and often requires it to have sound insulation, vibration damping, corrosion protection and other properties. The need for thermal insulation varies from aircraft to aircraft. Foam plastics, ultra-fine glass wool, and high-silicon oxygen foam are commonly used in aircraft cockpits and cockpits to insulate heat. The thermal insulation material used for the head of the missile was phenolic foam in the early days, and with the application of polyurethane foam with good temperature resistance, a single thermal insulation material was developed into a sandwich structure.
The thermal insulation method of the missile instrument compartment is to coat a layer of foaming paint several millimeters thick on the outer skin of the cabin, which is used as an anti-corrosion coating at room temperature, and when the aerodynamic heating reaches more than 200 °C, it will evenly foam and play a role in heat insulation. The artificial earth satellite is moving in an alternating environment of high temperature and low temperature, and it is necessary to use multi-layer thermal insulation materials with high reflective properties, which are generally composed of dozens of layers of aluminized film, aluminized polyester film and aluminized polyimide film. In addition, the development of surface insulation tiles has successfully solved the thermal insulation problem of the space shuttle, and also marks a higher level of thermal insulation material development.
