CN107190240A - A kind of high temperature solar energy selective absorption coating and preparation method thereof - Google Patents

Abstract

The invention discloses a high-temperature solar energy selective absorption coating, which comprises a heat absorbing body base, an absorbing layer and an anti-reflection layer in sequence, the heat absorbing body base is a polished stainless steel sheet, the material of the absorbing layer is zirconium carbide, and the anti-reflection layer The material is alumina. The invention also discloses a preparation method of the coating. Under the condition of air quality factor AM1.5, the coating prepared by the present invention has an absorptivity of ≥0.88 and an emissivity of £0.13; thermal stability tests show that the coating has good structural stability and high temperature stability, and can be used for a long time Use in a vacuum environment at 500°C. The coating has important application value in industrial and agricultural fields such as photothermal power generation, heavy oil exploitation, and seawater desalination. The preparation process of the invention is simple, the cost is low, and the invention has broad practical value and application prospect in solar heat utilization.

Description

A kind of high temperature solar energy selective absorption coating and preparation method thereof

technical field

The invention relates to a high-temperature solar energy selective absorption coating and a preparation method thereof, belonging to the technical field of solar thermal utilization.

Background technique

At present, under the background of increasingly scarce non-renewable energy sources such as fossils, the world's energy structure will undergo major changes, and solar energy will gradually replace conventional energy sources and become an indispensable and important energy source. Research on solar thermal utilization of solar energy has become a hot topic today. The high-temperature utilization of solar energy has broad market prospects in the fields of photothermal power generation, heavy oil extraction, and seawater desalination. Spectrum-selective absorbing coatings are core materials for high-temperature utilization of solar energy, which require high absorptivity, low emissivity and excellent high-temperature resistance.

In recent years, researchers have developed many transition metal nitride/carbide-based solar absorbing coatings with excellent properties, such as TiAlN/TiAlON/Si ₃ N ₄ , HfMoN/HfON/Al ₂ O ₃ , Ti/AlTiN/AlTiON/ AlTiO, Fe ₃ O ₄ /Mo/TiZrN/TiZrON/SiON, Ti _0.5 Al _0.5 N/Ti _0.25 Al _0.75 N/AlN, Cu/TiAlCrN/TiAlN/AlSiN, TiAlC/TiAlCN/TiAlSiCN/TiAlSiCO/TiAlSi, etc. However, the deposition process of this multilayer series system is relatively complicated, and the stoichiometric ratio needs to be precisely controlled, resulting in a long production cycle, complicated process, and high cost.

Contents of the invention

The technical problem to be solved by the present invention is to provide a high-temperature solar selective absorption coating with high visible-infrared spectrum high absorption rate and infrared spectrum low emissivity in view of the problems existing in traditional solar selective absorption coatings in the prior art.

Another object of the present invention is to provide a method for preparing the above-mentioned high-temperature solar selective absorption coating.

A high-temperature solar energy selective absorption coating, the coating sequentially includes a heat absorber base, an absorber layer and an anti-reflection layer, the heat absorber base is a polished stainless steel sheet, the material of the absorber layer is zirconium carbide, and the anti-reflection layer The reflective layer material is aluminum oxide.

The zirconium carbide absorbing layer has a thickness of 120-160 nm.

The aluminum oxide thickness of the anti-reflection layer is 80-120 nm.

The roughness value of the polished stainless steel sheet of the absorber base is 0.5-2 nm.

The preparation method of the above-mentioned high-temperature solar energy selective absorption coating comprises the following process steps:

1) Treatment of the endothermic substrate: After removing the impurities attached to the surface of the endothermic substrate, ultrasonically clean it in acetone and ethanol for 10-20 minutes respectively, dry it with nitrogen, and store it in vacuum;

2) Preparation of the absorbing layer: The zirconium carbide of the absorbing layer is prepared by the DC magnetron sputtering method, and zirconium carbide with a purity of 99.99% is used as the magnetron sputtering target; the vacuum chamber is pre-pumped to a background vacuum of 1.0´10 ^-6 -5.0´10 ^-6 Torr; use bias to clean the substrate for 5-10 minutes, and the bias power is 10-30W; start to deposit the absorbing layer after the bias is cleaned, and the sputtering power density of the zirconium carbide target is 4-8 W/cm ^-2 , the gas intake of argon during sputtering deposition is 20-50 sccm, and the thickness of deposited zirconium carbide is 120-160 nm;

3) Preparation of the anti-reflection layer: After the absorption layer is prepared, the anti-reflection layer Al ₂ O ₃ is deposited, and Al ₂ O ₃ with a purity of 99.99% is used as the magnetron sputtering target to control the Al ₂ O ₃ target The sputtering power density is 5-8 W/cm ^-2 , the intake of argon gas is 20-50 sccm during sputtering deposition, and the anti-reflection layer is prepared on the absorbing layer by radio frequency magnetron sputtering, with a thickness of 80 -120nm.

In the step 2), the substrate temperature of the heat absorber is 150-250° C. when the absorber layer is deposited by magnetron sputtering.

In the step 3), the substrate temperature of the heat absorber is 150-250° C. when the antireflection layer is deposited by magnetron sputtering.

The high-temperature solar selective absorbing coating of the present invention uses zirconium carbide with good high-temperature stability as the absorbing layer and the diffusion barrier layer, which greatly enriches the application of zirconium carbide ceramics in the solar energy industry. The solar selective coating of the invention has low reflectivity in the ultraviolet-visible-near-infrared spectrum range and high reflectivity in the infrared spectrum range. Under the condition of air quality factor AM1.5, the absorptivity is ≥0.88, and the emissivity is £0.13; under high vacuum, the absorptivity and emissivity of the coating have no obvious changes after a long time of holding at 500°C. The coating has important application value in industrial and agricultural fields such as photothermal power generation, heavy oil exploitation, and seawater desalination.

In summary, the coating prepared by the present invention has the characteristics of high absorption rate in the visible-infrared spectrum and low emissivity in the infrared spectrum. The zirconium carbide of the present invention is used as an absorbing layer and a diffusion barrier layer, without an infrared reflective layer and doping, and has a simple coating structure, thereby simplifying the process and reducing costs. The present invention has broad practical value and application prospects in the field of high-temperature solar heat utilization.

detailed description

The high temperature solar selective absorbing coating of the present invention as well as its preparation and performance will be further described through specific examples below.

Example 1

A high-temperature solar selective absorption coating, which sequentially includes a heat absorber substrate, an absorber layer and an anti-reflection layer. The heat absorber substrate is a polished stainless steel sheet with a roughness value of 1.2 nm; the material of the absorber layer is zirconium carbide with a thickness of 140 nm, the absorbing layer was prepared by DC magnetron sputtering; the material of the anti-reflection layer was aluminum oxide with a thickness of 90 nm, and the anti-reflection layer was prepared by radio frequency magnetron sputtering.

The preparation method of the above-mentioned high-temperature solar energy selective absorption coating comprises the following processes:

(1) Treatment of the heat absorber substrate: A polished stainless steel sheet with a roughness value of 1.2 nm was selected as the heat absorber substrate. Before use, wipe the surface with a cotton ball to remove impurities attached to the surface, then ultrasonically clean the polished stainless steel sheet in acetone and ethanol solvents for 15 minutes, blow dry with nitrogen, and store in vacuum until use;

(2) Preparation of the absorbing layer: The zirconium carbide of the absorbing layer was prepared by the DC magnetron sputtering method, and zirconium carbide with a purity of 99.99% was used as the magnetron sputtering target; the vacuum chamber was pre-pumped to a background vacuum of 3.0´10 ^{- 6} Torr; clean the substrate with a bias voltage of 20W for 5 minutes; start to deposit the absorber layer after the bias cleaning is completed, the sputtering power density of the zirconium carbide target is 6.5W/cm ^-2 , and the argon The gas intake volume is 30 sccm, the base temperature of the heat absorber is 200 °C when the absorber layer is deposited by magnetron sputtering, and the thickness of deposited zirconium carbide is 140 nm;

(3) Preparation of the anti-reflection layer: After the absorption layer is prepared, the anti-reflection layer Al ₂ O ₃ is deposited. Al ₂ O ₃ with a purity of 99.99% was used as the magnetron sputtering target, the sputtering power density of the Al ₂ O ₃ target was controlled at 6 W/cm ^-2 , and the intake of argon gas during sputtering deposition was 30 sccm, using radio frequency magnetron sputtering to sputter the anti-reflection layer on the absorber layer, when the anti-reflection layer is deposited by magnetron sputtering, the base temperature of the absorber is 200°C, and the thickness is 90 nm;

The optical properties of the solar selective absorbing coating are as follows: under the condition of air quality factor AM1.5, the absorptivity of the coating is 0.92, and the emissivity is 0.11; The rate is 0.93 and the normal emissivity is 0.10.

Example 2

A high-temperature solar selective absorption coating, which includes a heat absorber substrate, an absorber layer and an anti-reflection layer in sequence. The heat absorber substrate is a polished stainless steel sheet with a roughness value of 0.5 nm; the material of the absorber layer is zirconium carbide with a thickness of 120 nm, the absorbing layer was prepared by DC magnetron sputtering; the material of the anti-reflection layer was aluminum oxide with a thickness of 80 nm, and the anti-reflection layer was prepared by radio frequency magnetron sputtering.

The preparation method of the above-mentioned high-temperature solar energy selective absorption coating comprises the following processes:

(1) Treatment of the heat absorber substrate: A polished stainless steel sheet with a roughness value of 0.5 nm was selected as the heat absorber substrate. Before use, wipe the surface with a cotton ball to remove impurities attached to the surface, then ultrasonically clean the polished stainless steel sheet in acetone and ethanol solvents for 10 minutes, blow dry with nitrogen, and store in vacuum until use.

(2) Preparation of the absorbing layer: The zirconium carbide of the absorbing layer was prepared by the DC magnetron sputtering method, and zirconium carbide with a purity of 99.99% was used as the magnetron sputtering target; the vacuum chamber was pre-pumped to a background vacuum of 1.0´10 ^{- 6} Torr; clean the substrate with bias voltage for 10 minutes, and the bias power is 10W; start to deposit the absorbing layer after the bias cleaning is completed, the sputtering power density of the zirconium carbide target is 4 W/cm ^-2 , and the argon The gas intake volume is 20 sccm, the base temperature of the heat absorber is 150 °C when the absorber layer is deposited by magnetron sputtering, and the thickness of deposited zirconium carbide is 120 nm;

(3) Preparation of the anti-reflection layer: After the absorption layer is prepared, the anti-reflection layer Al ₂ O ₃ is deposited. Al ₂ O ₃ with a purity of 99.99% was used as the magnetron sputtering target, the sputtering power density of the Al ₂ O ₃ target was controlled at 5 W/cm ^-2 , and the intake of argon gas during sputtering deposition was 20 sccm, using radio frequency magnetron sputtering to sputter the anti-reflection layer on the absorber layer. When the anti-reflection layer is deposited by magnetron sputtering, the substrate temperature of the absorber is 150 ℃, and the thickness is 80 nm.

The optical properties of the solar selective absorbing coating are as follows: under the condition of air quality factor AM1.5, the absorptivity of the coating is 0.90, and the emissivity is 0.12; The ratio is 0.90 and the emissivity is 0.13.

Example 3

A high-temperature solar selective absorption coating, which sequentially includes a heat absorber substrate, an absorber layer and an anti-reflection layer. The heat absorber substrate is a polished stainless steel sheet with a roughness value of 2 nm; the material of the absorber layer is zirconium carbide with a thickness of 160 nm, the absorption layer was prepared by DC magnetron sputtering method; the material of the anti-reflection layer was aluminum oxide with a thickness of 120 nm, and the anti-reflection layer was prepared by radio frequency magnetron sputtering method.

The preparation method of the above-mentioned zirconium carbide-based high-temperature solar energy selective absorption coating includes the following processes:

(1) Treatment of the heat absorber substrate: A polished stainless steel sheet with a roughness value of 2 nm was selected as the heat absorber substrate. Before use, wipe the surface with a cotton ball to remove impurities attached to the surface, then use a stainless steel sheet to ultrasonically clean it in acetone and ethanol solvents for 20 minutes, dry it with nitrogen, and store it in vacuum until use;

(2) Preparation of the absorbing layer: The zirconium carbide of the absorbing layer was prepared by the DC magnetron sputtering method, and zirconium carbide with a purity of 99.99% was used as the magnetron sputtering target; the vacuum chamber was pre-pumped to a background vacuum of 5.0´10 ^{- 6} Torr; clean the substrate with bias voltage for 5 minutes, the bias power is 30W; start to deposit the absorber layer after the bias cleaning is completed, the sputtering power density of the zirconium carbide target is 8 W/cm ^-2 , and the argon The gas intake volume is 50 sccm, the base temperature of the heat absorber is 250 °C when the absorber layer is deposited by magnetron sputtering, and the thickness of deposited zirconium carbide is 160 nm;

(3) Preparation of the anti-reflection layer: After the absorption layer is prepared, the anti-reflection layer Al ₂ O ₃ is deposited. Al ₂ O ₃ with a purity of 99.99% was used as the magnetron sputtering target, the sputtering power density of the Al ₂ O ₃ target was controlled at 8 W/cm ^-2 , and the intake of argon gas during sputtering deposition was 50 sccm, using radio frequency magnetron sputtering to sputter the anti-reflection layer on the absorber layer. When depositing the anti-reflection layer by magnetron sputtering, the substrate temperature of the absorber is 250 ℃, and the thickness is 120 nm.

The optical properties of the solar selective absorbing coating are as follows: under the condition of air quality factor AM1.5, the absorptivity of the coating is 0.88, and the emissivity is 0.12; The ratio is 0.90 and the emissivity is 0.12.

Claims (7)

1. a kind of high temperature solar energy selective absorption coating, it is characterised in that the coating includes absorber substrate, absorbed layer successively And antireflection layer, the absorber substrate is polishing stainless steel piece, and the absorption layer material is zirconium carbide, the antireflection layer material Expect for aluminum oxide.

2. coating as claimed in claim 1, it is characterised in that the thickness of the absorbed layer zirconium carbide is 120-160 nm.

3. coating as claimed in claim 1, it is characterised in that the thickness of the antireflection layer aluminum oxide is 80-120 nm.

4. coating as claimed in claim 1, it is characterised in that the roughness value of the absorber substrate polish stainless steel substrates is 0.5-2 nm。

5. the preparation method of high temperature solar energy selective absorption coating as any one of Claims 1-4, including following work Skill step：

1）The processing of absorber substrate：After the impurity that absorber substrate is removed to surface attachment, divide respectively in acetone and ethanol Chao Shengqingxi not be 10-20 minutes, nitrogen drying, vacuum is preserved；

2）The preparation of absorbed layer：Absorbed layer zirconium carbide is prepared and uses DC magnetron sputtering method, and purity 99.99% is used during preparation Zirconium carbide be used as magnetic control spattering target；Vacuum chamber takes out base vacuum to 1.0 ' 10 in advance^-6-5.0´10^-6Torr；It is clear using bias Wash substrate 5-10 minutes, substrate bias power is 10-30W；Bias cleaning starts deposit absorbent layer, the sputtering of zirconium carbide target after terminating Power density is 4-8 W/cm^-2, the air inflow of argon gas is 20-50 sccm during sputtering sedimentation, and depositing silicon zirconium thickness is 120- 160 nm；

3）The preparation of antireflection layer：After absorbed layer preparation is finished, start deposition antireflection layer Al₂O₃, using purity as 99.99% Al₂O₃As magnetic control spattering target, Al is controlled₂O₃The Sputtering power density of target is in 5-8 W/cm^-2, argon gas during sputtering sedimentation Air inflow is 20-50 sccm, and using rf magnetron sputtering, sputtering prepares antireflection layer on absorbed layer, and thickness is 80-120 nm。

6. preparation method as claimed in claim 5, it is characterised in that the step 2）In in magnetron sputtering deposition absorbed layer The absorber base reservoir temperature is 150-250 DEG C.

7. preparation method as claimed in claim 5, it is characterised in that the step 3）In in magnetron sputtering deposition antireflection layer Shi Suoshu absorbers base reservoir temperature is 150-250 DEG C.