Evaporated Ag coated with double layers of Al 2O 3 and silicon oxide to produce surface films with low solar absorptivity and high thermal emissivity

Abstract

A technique using evaporated Ag coated with double layers of Al 2O 3 and silicon oxide to produce surface films having low solar absorptivity (α) and high total normal and hemispherical emissivities (ϵ N and ϵ) is described. α of the Ag + Al 2O 3 + silicon oxide film combination was determined to be less than 0.07 and α/ϵ values of 0.1 could be readily achieved. Surface films of this type were found to be extremely stable during simulated solar uv irradiation.