CN-122013278-A - Composite micro-arc oxidation coating, preparation method and application thereof and thermal control part

CN122013278ACN 122013278 ACN122013278 ACN 122013278ACN-122013278-A

Abstract

The application relates to the field of surface engineering, and discloses a composite micro-arc oxidation coating, a preparation method and application thereof, and a thermal control component. The composite micro-arc oxidation coating comprises a micro-arc oxidation base film layer, a lanthanum salt hole sealing film layer and a sol-gel film layer, wherein the lanthanum salt hole sealing film layer is filled in pores of the micro-arc oxidation base film layer, and the sol-gel film layer is coated on the surface of the micro-arc oxidation base film layer. According to the application, after the soluble lanthanum salt is adopted for pre-sealing holes on the micro-arc oxidation base film layer, a preliminary barrier is formed in the pore canal, then sol-gel post treatment is further adopted, a compact network is constructed on the surface layer, and the obtained composite micro-arc oxidation coating remarkably improves the corrosion resistance and ultraviolet aging resistance of the composite coating on the premise of not sacrificing the thermal control characteristic of alpha S /epsilon value, realizes the cooperative promotion of corrosion resistance and space environment adaptability, and meets the severe requirement of a long-life thermal control component on the protection of the light alloy surface.

Inventors

WEN CHEN
ZHONG JINGKANG
BAI JINGYING
YANG DONGCHENG
ZHANG ZISHUO
WU XIN
WANG YANYANG

Assignees

北京星驰恒动科技发展有限公司

Dates

Publication Date: 20260512
Application Date: 20251231

Claims (10)

1. The composite micro-arc oxidation coating is characterized by comprising a micro-arc oxidation base film layer, a lanthanum salt hole sealing film layer and a sol-gel film layer, wherein the lanthanum salt hole sealing film layer is filled in pores of the micro-arc oxidation base film layer, and the sol-gel film layer is coated on the surface of the micro-arc oxidation base film layer.
2. The composite micro-arc oxidation coating according to claim 1, wherein the micro-arc oxidation base film layer is formed by micro-arc oxidation of silicate system electrolyte, the lanthanum salt hole sealing film layer is formed by slow-release hydrolysis in-situ growth of lanthanum salt solution, and the sol-gel film layer is formed by curing zirconium doped silica sol.
3. The composite micro-arc oxidation coating according to claim 2, wherein the silicate system electrolyte comprises silicate, hydroxide and stabilizer, the lanthanum salt solution comprises soluble lanthanum salt, sodium chloride and hydrogen peroxide, and the zirconium doped silica sol comprises a silicon source, a zirconium source, an alcoholic solvent and water.
4. The composite micro-arc oxidation coating according to claim 2 or 3, wherein said silicate system electrolyte comprises 8-20g/L sodium silicate, 6-10g/L potassium hydroxide and 8-12g/L stabilizer, said lanthanum salt solution comprises 0.05-0.15 mol/L lanthanum acetate monohydrate, 0.03-0.07 mol/L sodium chloride and 1-2 vol% hydrogen peroxide, said zirconium doped silica sol comprises ethyl orthosilicate, zirconium oxychloride, ethanol and water, and the Zr/Si molar ratio is maintained in the range of 0.03-0.04 by adjusting the solution concentrations of ethyl orthosilicate and zirconium oxychloride.
5. The method for preparing the composite micro-arc oxidation coating according to claim 1, comprising the steps of: Performing micro-arc oxidation on the surface of the metal substrate by adopting silicate system electrolyte to form a micro-arc oxidation base film layer; Immersing the micro-arc oxidation base film layer in lanthanum salt solution, and then performing heat treatment reaction to diffuse lanthanum salt ions into pores of the micro-arc oxidation base film layer for hydrolytic deposition to form a La (OH) 3 /LaOOH lanthanum salt hole sealing film layer; Coating zirconium doped silica sol on the surface of the coating layer for forming the lanthanum salt hole sealing film layer, and curing to form a sol-gel film layer to obtain the composite micro-arc oxidation coating.
6. The method of claim 5, wherein the parameters of the micro-arc oxidation include: The bipolar pulse power supply is used, the frequency is 550-800 Hz, the duty ratio is 10%, the constant current mode is adopted, the current density is 6-10A/dm 2 , the treatment time is 10-30 min, and the electrolyte temperature is not higher than 30 o C.
7. The method of claim 5, wherein the zirconium doped silica sol is prepared by: Mixing silicon source, alcohol solvent and water, regulating pH value to 1.8-2.2, uniformly mixing, adding zirconium source, uniformly mixing, ageing and obtaining zirconium doped silicon dioxide sol.
8. Use of a composite micro-arc oxidation coating according to any one of claims 1 to 4 for the preparation of a thermal control component.
9. A thermal control component comprising a metal substrate and a thermal control coating disposed on a surface of the metal substrate, the thermal control coating comprising the composite micro-arc oxidation coating of any one of claims 1-4.
10. The thermal control component of claim 9 wherein the metal matrix comprises a light weight alloy.

Description

Composite micro-arc oxidation coating, preparation method and application thereof and thermal control part Technical Field The application relates to the field of surface engineering, in particular to a composite micro-arc oxidation coating, a preparation method and application thereof and a thermal control component. Background The magnesium alloy has become a key structural material for realizing light weight of a new generation of spacecraft due to the advantages of low density (1.74 g/cm 3), high specific strength, good shock absorption and the like. However, magnesium alloy has active chemical properties, is very easy to corrode in the atmosphere and space environment, and the natural oxide film is loose and porous, so that effective protection cannot be provided. For this reason, micro-arc oxidation (MAO) is widely used to form in situ a ceramic film based on MgO, mg 2SiO4, etc. on the surface of magnesium alloy. By regulating electrolyte components (such as silicate and phosphate systems) and electrical parameters, a coating with high whiteness, low solar absorption ratio (alpha S < 0.35) and high hemispherical emissivity (epsilon > 0.85) can be obtained, and the passive thermal control requirement of a spacecraft is met. However, the inherent microporous and microcracked structure (porosity typically up to 10-20%) of the micro-arc oxidized coating makes it a corrosion path in humid, salt fog or atomic oxygen environments, and has inadequate long-term service stability. In addition, spatially high energy ultraviolet radiation can cause photochemical aging of the coating surface, causing an increase in α S, disrupting the thermal control balance. Therefore, the effective hole sealing of the micro-arc oxidation film is a key link for improving the comprehensive performance of the micro-arc oxidation film. Disclosure of Invention In view of the above, the application aims to provide a composite micro-arc oxidation coating and a preparation method thereof, so that the composite micro-arc oxidation coating can remarkably improve corrosion resistance and ultraviolet aging resistance, and simultaneously further reduce solar absorption ratio (alpha S) and improve hemispherical emissivity (epsilon); another object of the present application is to provide the use of the composite micro-arc oxidation coating described above in the preparation of a thermal control component; it is another object of the present application to provide a thermal control component based on the composite micro-arc oxidation coating described above, such that the thermal control component has excellent properties resulting from the composite micro-arc oxidation coating described above. In order to solve the technical problems or at least partially solve the technical problems, as a first aspect of the present application, a composite micro-arc oxidation coating is provided, which comprises a micro-arc oxidation base film layer, a lanthanum salt hole sealing film layer and a sol-gel film layer, wherein the lanthanum salt hole sealing film layer is filled in pores of the micro-arc oxidation base film layer, and the sol-gel film layer is coated on the surface of the micro-arc oxidation base film layer. Optionally, the micro-arc oxidation base film layer is formed by micro-arc oxidation of silicate system electrolyte, the lanthanum salt hole sealing film layer is formed by curing lanthanum salt solution, and the sol-gel film layer is formed by curing zirconium doped silica sol. Further alternatively, the silicate system electrolyte comprises silicate, hydroxide and stabilizer, the lanthanum salt solution comprises soluble lanthanum salt, sodium chloride and hydrogen peroxide, and the zirconium doped silica sol comprises a silicon source, a zirconium source, an alcoholic solvent and water. Further alternatively, the method may comprise, in a further alternative, The silicate system electrolyte comprises 8-20g/L sodium silicate, 6-10g/L potassium hydroxide and 8-12g/L stabilizer, the lanthanum salt solution comprises 0.05-0.15 mol/L lanthanum acetate monohydrate, 0.03-0.07 mol/L sodium chloride and 1-2 vol% hydrogen peroxide, the zirconium doped silica sol comprises ethyl orthosilicate, zirconium oxychloride, ethanol and water, and the mole ratio of Zr/Si is maintained within the range of 0.03-0.04 by adjusting the solution concentration of the ethyl orthosilicate and the zirconium oxychloride. As a second aspect of the present application, there is provided a method for preparing the composite micro-arc oxidation coating according to the present application, comprising: Performing micro-arc oxidation on the surface of the metal substrate by adopting silicate system electrolyte to form a micro-arc oxidation base film layer; Immersing the micro-arc oxidation base film layer in lanthanum salt solution, and then performing heat treatment reaction to diffuse lanthanum salt ions into pores of the micro-arc oxidation base film layer for hydrolyti