High-temperature solar selective absorbing coating and preparation method thereof

Abstract

The invention provides a high-temperature solar selective absorbing coating and a preparation method thereof. According to the high-temperature solar selective absorbing coating, a metal material serves as a base material, and a metal reflection film layer, a diffusion stop film layer, an absorbing film layer and an antireflection film layer are arranged on the surface of the metal base material sequentially from inside to outside, wherein the absorbing film layer comprises four absorbing sublayers with metal contents decreasing in a gradient mode from inside to outside. The absorbing film layer comprises the four absorbing sublayers with the gradually varied metal contents, and the metal contents change in the gradient mode, so that diffusion of the coating is slight during the high-temperature work process, and the high temperature stability of the film layers is improved.

Description

technical field [0001] The invention relates to the technical field of solar energy utilization, in particular to a low-cost, high-temperature high-temperature solar selective absorption coating and a preparation method thereof. Background technique [0002] The solar spectrum selective absorption coating is a functional film with high absorption in the visible-near-infrared band and low emissivity in the infrared band. It is a key technology for solar collectors to improve the efficiency of light-to-heat conversion. With the continuous development of solar heat utilization requirements and technology, the application range of solar collector tubes has been developed from low temperature applications (≤100°C) to medium temperature applications (100°C-350°C) and high temperature applications (350°C-500°C). Meet the requirements of medium and high temperature applications such as seawater desalination and solar power generation. The selective absorption coating used for the h...

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Problems solved by technology

In the continuous practice of researching high-performance, high-stability, and long-life high-temperature solar selective absorption film systems, many different types of film structures have been used, such as SS-AlN / SS (stainless steel aluminum nitride), W -Al 2 o 3 、Mo-Al 2 o 3 , W-SiO 2 Equal coating, the structure of SS+ALN absorbing coating is composed of two metal-ceramic dielectric absorbing sub-layers. Since the metal content of the two metal-ceramic dielectric absorbing sub-layers is greatly different, the metal components in the coating are easy to diffuse in high temperature. The composition of the absorption sublayer changes, the optical properties of the coating decay, and the aging and peeling of the film layer result in the failure of the film layer, which limits the application of this coating in high temperature; Mo-Al 2 o 3 / Cu system is characterized by Mo-Al 2 o 3 The absorption sublayer has a complex multi-sublayer structure with gradual composition changes, and the process is complicated and difficult to control; Al 2 o 3 The layer adopts radio frequency sputtering method, the radio frequency sputtering equipment is complicated, and the deposition rate is low; W-Al 2 o 3 , W-SiO 2 The relatively expensive tungsten target and the sputtering silicon target of the planar target are used. The utilization rate of the target material of the planar silicon target is low, which greatly increases the cost of the film layer and hinders the further development of high-temperature applications of solar energy.

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