Space cryogenic heat control coating and preparation method thereof

The invention discloses a space cryogenic heat control coating and a preparation method thereof, and belongs to the field of new materials. The cryogenic heat control coating material is composed of a surface radiation layer, a middle reflection layer and a back protection layer, and the surface radiation layer has high long-wave infrared cut-off frequency, such as fluoride; the middle reflecting layer is used for efficiently reflecting solar heat flow, such as an Ag layer and an Al layer; the backside protection layer is used to protect spatial atomic oxygen oxidation of the coating, such as a nickel thin film layer. The prepared coating is of a fluoride/Ag/nickel three-layer composite structure. The solar absorption ratio of the coating is as low as 0.03, the infrared reflection cutoff wavelength is 8-12m, the heat balance temperature of the coating is as low as 50K, and the coating can be applied to thermal control systems of low-temperature equipment of various spacecrafts in space service. In addition, t