A high temperature solar power selective absorption coating with a Si3N4 and AlN double ceramic structure and a preparation method thereof

The invention provides a high temperature solar power selective absorption coating with a Si3N4 and AlN double ceramic structure and a preparation method thereof, belonging to a technology field of solar power utilization. An infrared emission layer, an absorbing layer, an antireflection layer are arranged in sequence from a bottom layer of the coating to a surface layer, wherein the first infrared emission layer consists of a Cu film or an Ag film, with a thickness ranging from 50 to 150 nm, the second layer absorbing layer includes a two-sublayer structure with both sublayers being an Si3N4 and AIN film, and the third antireflection layer is a SiO2 film with a thickness being 20 to 60 nm. The coating provided in the invention is characterized by a high absorption rate within a visible-infrared spectrum and a low emission rate within an infrared spectrum. The coating has favorable middle-and-high temperature heat stability by adopting an interference absorbing layer of the double ceramic structure. The coating has advantages of simply preparation technique, easy operation, easy control, and shortened production cycle.