Selective solar energy absorbing coating and method for making same

Abstract

The invention relates to a solar energy selective absorbing coating and a preparation method thereof. The coating comprises a substrate layer and an absorption layer, and is characterized in that a sediment blocking thermal diffusion film layer, a reflective layer, the absorption layer and a micro-irregular surface layer are arranged on the substrate layer; the substrate layer and the reflective layer are both Ni films; the blocking thermal diffusion film layer is a MgO film; the absorption layer is a composite ceramic film which is composed of a metal Ni and a medium MgO; and the micro-irregular surface layer is a Ni-C film and adopts the etching sputtering to form the rough and rugged surface. The coating has transmission-enhancing and wear-resistant properties, high absorption ratio of visible-near infrared spectra, extreme low emissivity of the infrared spectra, good stability of vacuum baking, high-temperature working temperature resistance of more than 300 DEG C, high absorption ratio and smaller emission. The preparation adopts the dual-target sputtering of a nickel target and a magnesium oxide target, which can improve the high-temperature using range, improve the thermal stability of the selective absorbing coating, reduce the infrared emissivity, simplify the production process and reduce the cost.

Description

technical field [0001] The invention relates to the technical field of solar heat collection, in particular to a selective absorption coating on the surface of a solar all-glass vacuum tube base material and a preparation method thereof. Background technique [0002] The important form of solar energy utilization is photothermal utilization, so the preparation of solar absorbing coatings has become an important process for solar photothermal utilization. The all-glass vacuum tube is a key component of solar water heaters and collectors, and the performance of its coating directly affects the thermal performance of solar water heaters and collectors. [0003] At present, the application range of solar thermal energy is mainly in the low temperature range (less than 100°C), and ordinary solar water heaters are mainly used, and the application range is for family, hotel bathing, domestic water and heating. This kind of water heater does not have high requirements on the temper...

AI Technical Summary

Problems solved by technology

The product coatings mainly used in this field have film layer structures such as W+ALN / W, Mo+ALN / Mo, etc. However, the key to this coating and process method is to use high-temperature stable metals such as W and Mo, resulting in Low deposition rate, long production cycle, complicated process, rare and expensive target materials, high cost

[0006] For selective coatings, most of the structures are reflective layer / absorbing layer / anti-reflective layer structure, most of the absorbing surface and anti-reflective surface adopt plane, especially the preparation of anti-reflective layer adopts plane, this structure is suitable for high temperature For absorbing coatings, the disadvantage is that the emissivity is higher in the high temperature region

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