Electrolyte solution for magnesium alloy surface micro-arc oxidation and preparation method of black coating

Abstract

The invention discloses an electrolyte solution for magnesium alloy surface micro-arc oxidation and a preparation method of a black coating. The electrolyte solution is prepared from a main film-forming agent, an auxiliary film-forming agent, main coloring salt, a complexing agent and deionized water; the main coloring salt is metal copper salt; the complexing agent is composed of condensed phosphate, organic phosphonate and tartrate; in the electrolyte solution, the content of the main film-forming agent is 5-50 g / L, the content of the auxiliary film-forming agent is 1-30 g / L, and the contentof the main coloring salt is 1-20 g / L; and the contents of various complexing agents can be compounded at 1-20 g / L. The electrolyte solution is not prone to precipitating in the micro-arc oxidation process, high in stability and long in service life; electrical parameters can be regulated and controlled in a large range, extreme discharge is not prone to occurring, and the film forming efficiencyis high; and the black coating prepared from the electrolyte solution is high in blackness, small in color difference, low in surface roughness, high in hardness, good in corrosion resistance, high in adhesive force, not prone to discoloring and excellent in thermal control performance.

Description

technical field [0001] The invention belongs to the technical field of metal surface treatment, and in particular relates to a preparation method of an electrolyte solution and a black coating for micro-arc oxidation on the surface of a magnesium alloy. Background technique [0002] Magnesium alloy, as the lightest metal in practical use, has broad application prospects in aerospace, weaponry, optoelectronic devices, 3C and other fields. However, in order to meet the service requirements of magnesium alloy products, it is necessary to prepare a layer of black coating on its surface. For example, the surface of the lens barrel of the optical device for deep space exploration needs to prepare a black coating with high absorption rate and low reflectivity to improve the measurement. Accuracy; space vehicle (satellite, spaceship, etc.) surface needs to prepare suitable solar light absorption rate (α s ) / emissivity (ε) ratio of black thermal control coating to ensure its normal ...

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Problems solved by technology

[0006] In view of the above-mentioned deficiencies in the prior art, the purpose of the present invention is to provide a method for preparing an electrolytic solution for micro-arc oxidation on the surface of magnesium alloys and a black coating. The electrolytic solution is not prone to precipitation during micro-arc oxidation and has high stability. It has a long service life; the electrolyte solution has high film-forming efficiency in the micro-arc oxidation process, and extreme discharge is not easy to occur during the film-forming stage. The electrical parameters can be adjusted in a wide range, and large-area workpieces can be prepared. The surface of the black coating is not prone to defects; the black coating prepared by using the electrolyte solution has high blackness, extremely small color difference, strong adhesion to the magnesium alloy substrate, and is not easy to decolorize, and the surface roughness of the coating is low; through doping Nanoparticles can further improve the wear and corrosion resistance of black coatings

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