Groove type solar medium-temperature selective absorption coating

[0024] Example 1

[0025] The trough-type solar energy medium-temperature absorption coating of the present invention includes four layers of films. From the substrate to the surface, there are an infrared reflection layer, a first absorption layer, a second absorption layer, and an anti-reflection layer. The infrared reflection layer is composed of Ni film and has a thickness of 20-120nm; the first absorption layer is a Ni+NiAl film with a thickness of 50-75nm, in which the content of NiAl is 25-35wt%; the second absorption layer is a Ni+NiAl film with a thickness of 75-150nm, The content of NiAl is 35-50wt%; the anti-reflection layer is a NiO film with a thickness of 25-50nm. The performance of the solar selective absorption coating prepared by the present invention is as follows: after the coating is annealed in vacuum at 400° C. for 1 hour, the coating absorption rate is 90%-92%.