阅读说明：本技术 一种太阳光谱选择性吸收涂层及其制备方法和应用 (Solar spectrum selective absorption coating and preparation method and application thereof ) 是由 王琬瑢 师晶 赵润强 于 2021-07-02 设计创作，主要内容包括：本发明公开了一种太阳光谱选择性吸收涂层及其制备方法和应用,属于太阳能光热利用技术领域。包括：通过溅射铬靶在预处理后的基底层材料上,沉积红外反射层；继续在惰性气体和甲烷的混合气氛中,首先通过同时溅射铬靶和石墨靶,在红外反射层上第一沉积吸收层；然后在第一沉积吸收层上继续通过同时溅射铬靶和石墨靶,第二沉积吸收层；最后关闭铬靶,继续通过溅射石墨靶,在第二沉积吸收层上沉积减反射层；自然冷却后,制得太阳光谱选择性吸收涂层；其中,通过调节石墨靶的靶电流,实现调节铬、碳元素的比例。本发明制得的太阳光谱选择性吸收涂层兼具高的光谱选择性吸收率和优异的耐磨性能,能够应用于制备太阳能平板集热器。(The invention discloses a solar spectrum selective absorption coating and a preparation method and application thereof, and belongs to the technical field of solar photo-thermal utilization. The method comprises the following steps: depositing an infrared reflecting layer on the pretreated substrate layer material by sputtering a chromium target; continuously sputtering a chromium target and a graphite target simultaneously in a mixed atmosphere of inert gas and methane to deposit an absorption layer on the infrared reflecting layer; then continuously sputtering a chromium target and a graphite target on the first deposition absorption layer at the same time to form a second deposition absorption layer; finally, closing the chromium target, continuing sputtering the graphite target, and depositing an antireflection layer on the second deposition absorption layer; after natural cooling, the solar spectrum selective absorption coating is prepared; wherein, the target current of the graphite target is adjusted to realize the adjustment of the proportion of the chromium element and the carbon element. The solar spectrum selective absorption coating prepared by the invention has high spectrum selective absorption rate and excellent wear resistance, and can be applied to the preparation of a solar flat plate collector.)

1. A preparation method of a solar spectrum selective absorption coating is characterized by comprising the following steps:

1) placing the clean substrate layer material in a vacuum cavity, and cleaning the substrate layer material by argon ions to obtain a pretreated substrate layer material;

2) in an inert atmosphere, depositing an infrared reflecting layer on the pretreated substrate layer material by sputtering a chromium target;

3) continuously sputtering a chromium target and a graphite target simultaneously in a mixed atmosphere of inert gas and methane to obtain a first deposition absorption layer on the infrared reflection layer; then continuously sputtering a chromium target and a graphite target on the obtained first deposition absorption layer at the same time to obtain a second deposition absorption layer; finally, closing the chromium target, continuing sputtering the graphite target, and depositing an antireflection layer on the obtained second deposition absorption layer;

4) after natural cooling, the solar spectrum selective absorption coating is prepared;

wherein, the target current of the graphite target is adjusted in the step 3) to realize the adjustment of the proportion of the elements of chromium and carbon.

2. The method for preparing solar spectrum selective absorption coating according to claim 1, wherein the vacuum degree of the vacuum chamber is pumped to 1.0 x 10 by a mechanical pump, a roots pump and a turbo-molecular pump in sequence^-4Pascal;

the substrate material is an aluminum alloy with surface smoothness Ra <1 μm and surface free of rusty spots and pits.

3. The method for preparing a solar spectrum selective absorption coating according to claim 1, wherein the operating parameters for performing argon ion cleaning in step 1) comprise: in an argon atmosphere, keeping the air pressure in the vacuum cavity at 0.5-0.6 Pa and the current intensity of the ion source at 2-3A in the bombardment process; the bias voltage of the direct current pulse is 600-1200V, the duty ratio is 50% -80%, and the frequency is 40-80 KHz.

4. The method for preparing a solar spectrum selective absorption coating according to claim 1, wherein the operating parameters for depositing the infrared reflecting layer in step 2) comprise: the voltage of the chromium target is 400-600V, the current is 0.8-2A, the working pressure is 0.7-1 Pa, the flow of argon is 120-160 sccm, and the deposition time is 10-12 min.

5. The method for preparing a solar spectrum selective absorption coating according to claim 1, wherein the operating parameters of the first deposited absorption layer or the second deposited absorption layer in step 2) comprise: the voltage of the chromium target is 400-600V, and the current is 0.8-2A; the graphite target voltage is 470-600V, and the current is 3-12A; the working pressure is 0.6-0.9 Pa, the argon flow is 120-160 sccm, the methane flow is 80-100 sccm, and the deposition time is 15-20 min.

6. The method for preparing a solar spectrum selective absorption coating according to claim 1, wherein the operating parameters for depositing the anti-reflection layer in step 2) comprise: the graphite target voltage is 101-606V, the current is 0.1-0.2A, the working pressure is 0.8-1.3 Pa, the argon flow is 120-160 sccm, and the deposition time is 7-24 min.

7. A solar spectrum selective absorption coating prepared by the preparation method of any one of claims 1 to 6.

8. The solar spectrum selective absorption coating according to claim 7, wherein the absorptivity of the solar spectrum selective absorption coating is 94-96%, and the emissivity is 5-8%.

9. Use of a solar spectrum selective absorber coating according to any of claims 7 or 8 for the preparation of a solar flat panel collector.

Technical Field

The invention belongs to the technical field of solar photo-thermal utilization, and relates to a solar spectrum selective absorption coating, and a preparation method and application thereof.

Background

With the development of civilization of human society, people face more and more problems and challenges in the aspect of energy, and various countries around the world put attention to the development and utilization of new energy. Since the problem of energy development is closely related to international political, safety, and economic issues, a strategy for encouraging the development of new energy is established to promote its rapid development. Among them, solar energy is playing an increasingly important role in human activities as a new energy source. The existing magnetron sputtering coating technology has severer production conditions, can prepare the spectral selective absorption coating which is suitable for the middle-high temperature field in the future, but can obtain good performance only by a large amount of parameter debugging and coating design, and the absorptivity of most of the current spectral selective absorption coating is lower than 92 percent, and the wear resistance is poor.

Disclosure of Invention

In order to overcome the defects of the prior art, the invention aims to provide a solar spectrum selective absorption coating, a preparation method and application thereof, and solves the problems of low absorptivity and poor wear resistance of a common solar photo-thermal selective absorption coating.

In order to achieve the purpose, the invention adopts the following technical scheme to realize the purpose:

the invention discloses a preparation method of a solar spectrum selective absorption coating, which comprises the following steps:

1) placing the clean substrate layer material in a vacuum cavity, and cleaning the substrate layer material by argon ions to obtain a pretreated substrate layer material;

2) in an inert atmosphere, depositing an infrared reflecting layer on the pretreated substrate layer material by sputtering a chromium target;

3) continuously sputtering a chromium target and a graphite target simultaneously in a mixed atmosphere of inert gas and methane to obtain a first deposition absorption layer on the infrared reflection layer; then continuously sputtering a chromium target and a graphite target on the obtained first deposition absorption layer at the same time to obtain a second deposition absorption layer; finally, closing the chromium target, continuing sputtering the graphite target, and depositing an antireflection layer on the obtained second deposition absorption layer;

4) after natural cooling, the solar spectrum selective absorption coating is prepared;

wherein, the target current of the graphite target is adjusted in the step 3) to realize the adjustment of the proportion of the elements of chromium and carbon.

Preferably, the vacuum degree of the vacuum cavity is pumped to 1.0 x 10 by a mechanical pump, a roots pump and a turbo molecular pump in sequence^-4Pascal;

the substrate material is an aluminum alloy with surface smoothness Ra <1 μm and surface free of rusty spots and pits.

Preferably, in step 1), the operating parameters for performing the argon ion cleaning include: in an argon atmosphere, keeping the air pressure in the vacuum cavity at 0.5-0.6 Pa and the current intensity of the ion source at 2-3A in the bombardment process; the bias voltage of the direct current pulse is 600-1200V, the duty ratio is 50% -80%, and the frequency is 40-80 KHz.

Preferably, the operating parameters for depositing the infrared reflecting layer in step 2) include: the voltage of the chromium target is 400-600V, the current is 0.8-2A, the working pressure is 0.7-1 Pa, the flow of argon is 120-160 sccm, and the deposition time is 10-12 min.

Preferably, in step 2), the operating parameters of the first deposition absorption layer or the second deposition absorption layer include: the voltage of the chromium target is 400-600V, and the current is 0.8-2A; the graphite target voltage is 470-600V, and the current is 3-12A; the working pressure is 0.6-0.9 Pa, the argon flow is 120-160 sccm, the methane flow is 80-100 sccm, and the deposition time is 15-20 min.

Preferably, the operating parameters for depositing the antireflection layer in step 2) include: the graphite target voltage is 101-606V, the current is 0.1-0.2A, the working pressure is 0.8-1.3 Pa, the argon flow is 120-160 sccm, and the deposition time is 7-24 min.

The invention discloses a solar spectrum selective absorption coating prepared by the preparation method.

Preferably, the absorptivity of the solar spectrum selective absorption coating reaches 94% -96%, and the emissivity is 5% -8%.

The invention discloses an application of the solar spectrum selective absorption coating in preparation of a solar flat plate collector.

Compared with the prior art, the invention has the following beneficial effects:

the invention discloses a preparation method of a solar spectrum selective absorption coating, which comprises the steps of 3) co-sputtering a second deposition absorption layer, adjusting graphite target current, adjusting chromium carbide nanocrystalline content to change microstructure, enabling particles to be effectively diffused more uniformly and compactly at high temperature, and improving absorption rate. Therefore, the solar spectrum selective absorption coating has the advantages of selective absorption and wear resistance, and can effectively solve the problems of low absorptivity and poor wear resistance of the common solar photo-thermal selective absorption coating of the existing material.

The invention also discloses a solar spectrum selective absorption coating prepared by the preparation method, the effect of improving the solar spectrum selective absorption rate can be achieved by embedding the chromium carbide nano-crystal into an amorphous carbon mechanism, and the wear resistance of the solar spectrum selective absorption coating can be improved by the diamond-like carbon coating. Therefore, the invention can prepare the solar spectrum selective absorption coating with very high wear resistance coefficient and very good wear resistance.

The invention also discloses application of the solar spectrum selective absorption coating in preparation of a solar flat plate collector. Based on the high absorption, low emission and excellent wear resistance of the solar spectrum selective absorption coating, the photo-thermal conversion efficiency and the service life of the flat plate type heat collector can be greatly improved.

Drawings

FIG. 1 is an SEM image of the surface topography of the solar spectrum selective absorption coating of the invention.

Detailed Description

In order to make the technical solutions of the present invention better understood, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

It should be noted that the terms "first," "second," and the like in the description and claims of the present invention and in the drawings described above are used for distinguishing between similar elements and not necessarily for describing a particular sequential or chronological order. It is to be understood that the data so used is interchangeable under appropriate circumstances such that the embodiments of the invention described herein are capable of operation in sequences other than those illustrated or described herein. Furthermore, the terms "comprises," "comprising," and "having," and any variations thereof, are intended to cover a non-exclusive inclusion, such that a process, method, system, article, or apparatus that comprises a list of steps or elements is not necessarily limited to those steps or elements expressly listed, but may include other steps or elements not expressly listed or inherent to such process, method, article, or apparatus.

The invention discloses a preparation method of a solar spectrum selective absorption coating, which comprises the following steps:

aluminum alloy is adopted as a base layer material, and the base layer material is placed into a vacuum cavity of a magnetron sputtering coating machine after being cleaned and dried by ultrasonic; the vacuum degree of the vacuum cavity is pumped to 1.0 multiplied by 10 by a mechanical pump, a roots pump and a turbo molecular pump in sequence^-4Pascal; before the film is deposited, introducing a certain amount of argon gas into the vacuum cavity, and cleaning the substrate by argon ions to remove an oxide layer, pollutants and burrs on the surface of the substrate; preparing an infrared reflecting layer on the substrate by sputtering a chromium target, introducing a certain amount of argon, simultaneously sputtering the chromium target and a graphite target to deposit a first deposition absorption layer and a second deposition absorption layer, closing the chromium target, introducing a certain amount of argon, and sputtering the graphite target to deposit an antireflection layer; and naturally cooling to obtain the solar spectrum selective absorption coating.

The depositable substrate material may be an industrial aluminium alloy with a surface finish Ra <1 μm, surface free of rust spots, pits.

When the argon ions are used for cleaning the substrate, argon with the purity of more than 99.99 percent is introduced, the air pressure in the cavity is kept at 0.5-0.6 Pa and the current intensity of the ion source is kept at 2-3A in the bombardment process; the bias voltage of the direct current pulse is 600-1200V, the duty ratio is 50% -80%, the frequency is 40-80 KHz, and the bombardment time is 10 min.

When the infrared reflecting layer is deposited, the voltage of the chromium target is 400-600V, the current is 0.8-2A, the working pressure is 0.7-1 Pa, the flow of argon is 120-160 sccm, and the deposition time is 10-12 min.

When the first absorption layer is deposited, the voltage of the chromium target is 400-600V, the current is 0.8-2A, the voltage of the graphite target is 470-600V, the current is 3-12A, the working pressure is 0.6-0.9 Pa, the flow rate of argon is 120-160 sccm, the flow rate of methane is 80-100 sccm, and the deposition time is 10-15 min.

When the second absorption layer is deposited, the voltage of the chromium target is 400-600V, the current is 0.8-2A, the voltage of the graphite target is 470-600V, the current is 3-12A, the working pressure is 0.6-0.9 Pa, the flow rate of argon is 120-160 sccm, the flow rate of methane is 80-100 sccm, and the deposition time is 15-20 min.

When the antireflection layer is deposited, the graphite target voltage is 101-606V, the current is 0.1-0.2A, the working pressure is 0.8-1.3 Pa, the argon flow is 120-160 sccm, the methane flow is 80-100 sccm, and the deposition time is 7-24 min.

Specifically, in the embodiment of the invention, in the prepared solar spectrum selective absorption coating, the thickness of the infrared reflection layer is 70-80 nm; the thickness of the absorption layer is 50-160 nm; the thickness of the antireflection layer is 50-180 nm, the sp2 hybrid bond content is 60% -65%, and the reflectivity is 2.2-3.3.

The solar spectrum selective absorption coating can be applied to the preparation of a solar flat plate collector.

The performance of the solar spectrum selective absorption coating prepared on the aluminum alloy substrate with the brand number of 1235 is evaluated by adopting an ultraviolet/visible light/near infrared spectrophotometer (provided with a 150mm integrating sphere) and an infrared spectrometer (provided with an A562-G/Q integrating sphere). And (3) testing results: the absorptivity of the solar spectrum selective absorption coating on the 1235 aluminum alloy substrate reaches 94-96%, and the emissivity is 5-8%. The invention has simple process and can realize the production of solar spectrum selective absorption coatings on different grades of industrial aluminum alloys.

The invention is described in further detail below with reference to the following figures and specific examples:

example 1

1, surface roughness Ra<A 1235 aluminum alloy with the size of 1 mu m, rust-free points and pits on the surface is subjected to ultrasonic cleaning and drying and then is filled into a vacuum cavity of a magnetron sputtering coating machine; the vacuum degree of the vacuum cavity is pumped to 1.0 multiplied by 10 by a mechanical pump, a roots pump and a turbo molecular pump in sequence^-4Pascal;

2, introducing argon gas with the purity of 99.999 percent of 160sccm into the vacuum cavity, cleaning the substrate with argon ions, removing an oxide layer, pollutants and burrs on the surface of the substrate, and keeping the air pressure in the cavity at 0.5Pa and the current intensity of the ion source at 2A in the bombardment process; the bias voltage of the direct current pulse is 600V, the duty ratio is 50%, the frequency is 40KHz, and the bombardment time is 10 min.

3, introducing argon with the purity of 99.999 percent of 120sccm into the vacuum cavity; and (3) adjusting the voltage of the chromium target to 400V, the current to 0.8A and the working pressure to 0.7Pa to deposit the infrared reflecting layer, wherein the deposition time is 10 min.

4, introducing argon with the purity of 99.999 percent of 120sccm into the vacuum cavity; adjusting the voltage of a chromium target to 400V, the current to 0.8A, the voltage of a graphite target to 470V, the current to 3A, the working pressure to 0.6Pa and the methane flow to 80sccm to deposit the absorption layer for 10 min.

5, introducing argon with the purity of 99.999 percent of 120sccm into the vacuum cavity; and adjusting the voltage of the chromium target to 400V, the current to 0.8A, the voltage of the graphite target to 470V, the current to 3A, the working pressure to 0.6Pa and the methane flow to 80sccm to deposit the absorption layer for 15 min.

6, introducing argon with the purity of 99.999 percent of 120sccm into the vacuum cavity; and (3) adjusting the graphite target voltage to be 101V, the current to be 0.1A and the working pressure to be 0.8Pa to deposit the antireflection layer, wherein the deposition time is 7 min.

And 7, taking out after the temperature in the vacuum cavity is cooled to room temperature, and obtaining the solar spectrum selective absorption coating. Referring to fig. 1, for the solar spectrum selective absorption coating prepared in example 1 of the present invention, a solar spectrum selective absorption coating prepared on a 1235 aluminum alloy substrate of the present invention was evaluated for performance using an ultraviolet/visible/near infrared spectrophotometer (equipped with a 150mm integrating sphere) and an infrared spectrometer (equipped with an a562-G/Q integrating sphere). And (3) testing results: the absorptivity of the solar spectrum selective absorption coating on the 1235 aluminum alloy substrate reaches 95%, and the emissivity is 7%.

Example 2

1, surface roughness Ra<A 1235 aluminum alloy with the size of 1 mu m, rust-free points and pits on the surface is subjected to ultrasonic cleaning and drying and then is filled into a vacuum cavity of a magnetron sputtering coating machine; the vacuum degree of the vacuum cavity is pumped to 1.0 multiplied by 10 by a mechanical pump, a roots pump and a turbo molecular pump in sequence^-4Pascal;

2, introducing argon gas with the purity of 99.999 percent of 160sccm into the vacuum cavity, cleaning the substrate with argon ions, removing an oxide layer, pollutants and burrs on the surface of the substrate, and keeping the air pressure in the cavity at 0.6Pa and the current intensity of the ion source at 3A in the bombardment process; the bias voltage of the direct current pulse is 1200V, the duty ratio is 80 percent, the frequency is 80KHz, and the bombardment time is 10 min.

3, introducing argon with the purity of 99.999 percent of 160sccm into the vacuum cavity; and (3) adjusting the voltage of the chromium target to 600V, the current to 2A and the working pressure to 1Pa to deposit the infrared reflecting layer, wherein the deposition time is 12 min.

4, introducing argon with the purity of 99.999 percent of 160sccm into the vacuum cavity; adjusting the voltage of a chromium target to 600V, the current to 2A, the voltage of a graphite target to 600V, the current to 12A, the working pressure to 0.9Pa and the methane flow to 100sccm to deposit the absorption layer for 15 min.

5, introducing argon with the purity of 99.999 percent of 160sccm into the vacuum cavity; and adjusting the voltage of the chromium target to 400V, the current to 2A, the voltage of the graphite target to 600V, the current to 12A, the working pressure to 0.9Pa and the methane flow to 100sccm to deposit the absorption layer for 20 min.

6, introducing argon with the purity of 99.999 percent of 160sccm into the vacuum cavity; and adjusting the graphite target voltage to 606V, the current to 0.2A and the working pressure to 1.3Pa to deposit the antireflection layer, wherein the deposition time is 24 min.

And 7, taking out after the temperature in the vacuum cavity is cooled to room temperature, and obtaining the solar spectrum selective absorption coating.

For the solar spectrum selective absorption coating prepared in the embodiment 2 of the invention, an ultraviolet/visible light/near infrared spectrophotometer (equipped with a 150mm integrating sphere) and an infrared spectrometer (equipped with an A562-G/Q integrating sphere) are adopted to evaluate the performance of the solar spectrum selective absorption coating prepared on a No. 1235 aluminum alloy substrate. And (3) testing results: the absorptivity of the solar spectrum selective absorption coating on the 1235 aluminum alloy substrate reaches 95%, and the emissivity is 6%.

Example 3

1, surface roughness Ra<A 1235 aluminum alloy with the size of 1 mu m, rust-free points and pits on the surface is subjected to ultrasonic cleaning and drying and then is filled into a vacuum cavity of a magnetron sputtering coating machine; the vacuum degree of the vacuum cavity is pumped to 1.0 multiplied by 10 by a mechanical pump, a roots pump and a turbo molecular pump in sequence^-4Pascal;

2, introducing argon gas with the purity of 99.999 percent of 160sccm into the vacuum cavity, cleaning the substrate with argon ions, removing an oxide layer, pollutants and burrs on the surface of the substrate, and keeping the air pressure in the cavity at 0.52Pa and the current intensity of the ion source at 2.8A in the bombardment process; the bias voltage of the direct current pulse is 1000V, the duty ratio is 70%, the frequency is 60KHz, and the bombardment time is 10 min.

3, introducing 150sccm argon with the purity of 99.999 percent into the vacuum cavity; and (3) adjusting the voltage of the chromium target to 550V, the current to 1.5A and the working pressure to 0.9Pa to deposit the infrared reflecting layer, wherein the deposition time is 11 min.

4, introducing 150sccm argon with the purity of 99.999 percent into the vacuum cavity; regulating the voltage of a chromium target to 550V, the current to 1.5A, the voltage of a graphite target to 550V, the current to 10A, the working pressure to 0.8Pa and the methane flow to 95sccm to deposit the absorption layer for 14 min.

5, introducing 150sccm argon with the purity of 99.999 percent into the vacuum cavity; and regulating the voltage of the chromium target to be 550V, the current to be 1.5A, the voltage of the graphite target to be 550V, the current to be 10A, the working pressure to be 0.8Pa and the methane flow to be 95sccm to deposit the absorption layer for the second time, wherein the deposition time is 18 min.

6, introducing 150sccm argon with the purity of 99.999 percent into the vacuum cavity; and adjusting the graphite target voltage to 500V, the current to 0.14A and the working pressure to 1.1Pa to deposit the antireflection layer, wherein the deposition time is 20 min.

And 7, taking out after the temperature in the vacuum cavity is cooled to room temperature, and obtaining the solar spectrum selective absorption coating.

For the solar spectrum selective absorption coating prepared in the embodiment 3 of the invention, an ultraviolet/visible light/near infrared spectrophotometer (equipped with a 150mm integrating sphere) and an infrared spectrometer (equipped with an A562-G/Q integrating sphere) are adopted to evaluate the performance of the solar spectrum selective absorption coating prepared on a No. 1235 aluminum alloy substrate. And (3) testing results: the absorptivity of the solar spectrum selective absorption coating on the 1235 aluminum alloy substrate reaches 94 percent, and the emissivity is 5 percent.

Example 4

1, surface roughness Ra<A 1235 aluminum alloy with the size of 1 mu m, rust-free points and pits on the surface is subjected to ultrasonic cleaning and drying and then is filled into a vacuum cavity of a magnetron sputtering coating machine; the vacuum degree of the vacuum cavity is pumped to 1.0 multiplied by 10 by a mechanical pump, a roots pump and a turbo molecular pump in sequence^-4Pascal;

2, introducing argon gas with the purity of 99.999 percent of 160sccm into the vacuum cavity, cleaning the substrate with argon ions, removing an oxide layer, pollutants and burrs on the surface of the substrate, and keeping the air pressure in the cavity at 0.58Pa and the current intensity of the ion source at 2.2A in the bombardment process; the bias voltage of the direct current pulse is 800V, the duty ratio is 60%, the frequency is 70KHz, and the bombardment time is 10 min.

3, introducing 130sccm argon with the purity of 99.999 percent into the vacuum cavity; and (3) adjusting the voltage of the chromium target to be 500V, the current to be 1.0A and the working pressure to be 0.8Pa to deposit the infrared reflecting layer, wherein the deposition time is 11 min.

4, introducing 130sccm argon with the purity of 99.999 percent into the vacuum cavity; and regulating the voltage of a chromium target to be 500V, the current to be 1.0A, the voltage of a graphite target to be 500V, the current to be 8A, the working pressure to be 0.7Pa and the methane flow to be 85sccm to deposit the absorption layer for the first time, wherein the deposition time is 13 min.

5, introducing 130sccm argon with the purity of 99.999 percent into the vacuum cavity; and regulating the voltage of the chromium target to be 500V, the current to be 1.0A, the voltage of the graphite target to be 500V, the current to be 8A, the working pressure to be 0.7Pa and the methane flow to be 85sccm to deposit the absorption layer for the second time, wherein the deposition time is 17 min.

6, introducing 130sccm argon with the purity of 99.999 percent into the vacuum cavity; and adjusting the graphite target voltage to 400V, the current to 0.18A and the working pressure to 0.9Pa to deposit the antireflection layer, wherein the deposition time is 10 min.

And 7, taking out after the temperature in the vacuum cavity is cooled to room temperature, and obtaining the solar spectrum selective absorption coating.

For the solar spectrum selective absorption coating prepared in the embodiment 4 of the invention, an ultraviolet/visible light/near infrared spectrophotometer (equipped with a 150mm integrating sphere) and an infrared spectrometer (equipped with an A562-G/Q integrating sphere) are adopted to evaluate the performance of the solar spectrum selective absorption coating prepared on a No. 1235 aluminum alloy substrate. And (3) testing results: the absorptivity of the solar spectrum selective absorption coating on the 1235 aluminum alloy substrate reaches 96%, and the emissivity is 8%.

Example 5

1, surface roughness Ra<A 1235 aluminum alloy with the size of 1 mu m, rust-free points and pits on the surface is subjected to ultrasonic cleaning and drying and then is filled into a vacuum cavity of a magnetron sputtering coating machine; the vacuum degree of the vacuum cavity is pumped to 1.0 multiplied by 10 by a mechanical pump, a roots pump and a turbo molecular pump in sequence^-4Pascal;

2, introducing argon gas with the purity of 99.999 percent of 160sccm into the vacuum cavity, cleaning the substrate with argon ions, removing an oxide layer, pollutants and burrs on the surface of the substrate, and keeping the air pressure in the cavity at 0.55Pa and the current intensity of the ion source at 2.5A in the bombardment process; the bias voltage of the direct current pulse is 900V, the duty ratio is 65%, the frequency is 50KHz, and the bombardment time is 10 min.

3, introducing 140sccm argon with the purity of 99.999 percent into the vacuum cavity; and (3) adjusting the voltage of the chromium target to 450V, the current to 1.8A and the working pressure to 0.85Pa to deposit the infrared reflecting layer, wherein the deposition time is 12 min.

4, introducing 140sccm argon with the purity of 99.999 percent into the vacuum cavity; and regulating the voltage of the chromium target to be 450V, the current to be 1.8A, the voltage of the graphite target to be 530V, the current to be 6A, the working pressure to be 0.75Pa and the methane flow to be 90sccm to deposit the absorption layer for the first time, wherein the deposition time is 12 min.

5, introducing 140sccm argon with the purity of 99.999 percent into the vacuum cavity; and adjusting the voltage of the chromium target to be 450V, the current to be 1.8A, the voltage of the graphite target to be 530V, the current to be 6A, the working pressure to be 0.75Pa and the methane flow to be 90sccm to deposit the absorption layer for the second time, wherein the deposition time is 18 min.

6, introducing 140sccm argon with the purity of 99.999 percent into the vacuum cavity; and (3) adjusting the graphite target voltage to 300V, the current to 0.16A and the working pressure to 1.2Pa to deposit the antireflection layer, wherein the deposition time is 15 min.

And 7, taking out after the temperature in the vacuum cavity is cooled to room temperature, and obtaining the solar spectrum selective absorption coating.

For the solar spectrum selective absorption coating prepared in the embodiment 5 of the invention, an ultraviolet/visible light/near infrared spectrophotometer (equipped with a 150mm integrating sphere) and an infrared spectrometer (equipped with an A562-G/Q integrating sphere) are adopted to evaluate the performance of the solar spectrum selective absorption coating prepared on a No. 1235 aluminum alloy substrate. And (3) testing results: the absorptivity of the solar spectrum selective absorption coating on the 1235 aluminum alloy substrate reaches 96%, and the emissivity is 7%.

In summary, the invention discloses a preparation method of a solar spectrum selective absorption coating. The multilayer composite solar spectrum selective absorption coating realizes the preparation of the multilayer composite solar spectrum selective absorption coating by adopting a non-equilibrium magnetron sputtering technology and matching with a direct current pulse ion source to improve the plasma density of a coating area. An infrared reflecting layer, an absorbing layer and an antireflection layer are sequentially arranged on the surface of the solar spectrum selective absorbing coating; the infrared reflecting layer is a sputtering deposition layer of metal Cr and has the function of reducing the infrared emissivity of the coating; the absorption layer is a sputtering deposition layer containing CrC/a-C: H and has the function of absorbing solar radiation; the antireflection layer is a sputtering deposition layer of a-C: H, and has the functions of reducing the reflection of the surface to incident solar rays and improving the surface absorption performance. The solar spectrum selective absorption coating prepared by the invention has high absorptivity and low emissivity, and can greatly improve the photo-thermal conversion efficiency of the flat plate type heat collector.

According to the novel solar spectrum selective absorption coating designed by the preparation method, in the coating structure, the diamond-like carbon coating is applied to the antireflection layer to improve the wear resistance of the coating, the chromium carbide nanocrystals are embedded into an amorphous carbon mechanism to improve the absorptivity, and the wear-resistant coating with high absorptivity and low emissivity is prepared.

The hydrogen-containing diamond-like carbon film (DLC or a-C: H for short) can be used as an antireflection coating with excellent performance, and is an optical film which has the advantages of higher hardness, high chemical stability and corrosion resistance, high thermal conductivity, high light transmittance (visible and near infrared bands) and the like under specific conditions. Wherein the proportion of the heterochemical bonds and the hydrogen content cause the difference of the microstructure, the mechanical property, the optical property and the like of the film layer.

For the amorphous/nanocrystalline structure film formed by doping metal Cr, doping elements are not uniformly distributed, but are dispersed in an amorphous matrix in the mode of metal carbon (MeC) nanoparticle clusters, and the mechanism of the nano surface effect shows that the crystal field environment and the bonding energy of surface atoms are different from those of internal atoms, and the crystal field is micronized along with the increase of surface active atoms, so that the surface energy of the amorphous/nanocrystalline structure film is greatly increased. The surface atoms have a plurality of dangling bonds, have unsaturation and are easy to combine with other atoms for stabilization. If the metal carbide is embedded in the amorphous matrix, the two phases are firmly combined, and the surface energy of the two phases is obviously reduced, so that the solar spectrum absorption material integrating excellent mechanical property, optical property and chemical stability can be formed. Meanwhile, the hydrogen-containing amorphous carbon is used as an antireflection layer, so that the film is endowed with excellent abrasion resistance while the optical performance is optimized. Therefore, in order to better popularize the flat plate collector, the solar spectrum selective absorption coating can be used for preparing the solar flat plate collector, has excellent mechanical property, high absorptivity, low emissivity and high wear resistance, and has important significance for industrial application.

The above-mentioned contents are only for illustrating the technical idea of the present invention, and the protection scope of the present invention is not limited thereby, and any modification made on the basis of the technical idea of the present invention falls within the protection scope of the claims of the present invention.