Preparation method of black thermal control coating on surface of light alloy

Abstract

The invention relates to a preparation method of a black thermal control coating on the surface of a light alloy. The method comprises the following steps that (1) after being ground, a light alloy sample is cleaned and dried to obtain the treated light alloy sample; (2) a micro-arc oxidation electrolyte is prepared, wherein a film forming agent, a coloring agent, a stabilization agent and a pH value adjusting agent are added into deionized water, and after even mixing, the micro-arc oxidation electrolyte with the pH value ranging from 9 to 13 is obtained; and (3) one kind of metal in an aluminum alloy, a magnesium alloy and a titanium alloy is adopted as an anode, stainless steel is adopted as a cathode, the treated light alloy sample is soaked in the micro-arc oxidation electrolyte, circulation cooling is started, the treated light alloy sample is subjected to micro-arc oxidation treatment through a bipolar pulse power source, and after micro-arc oxidation treatment is completed, thesample is taken out and is washed with water and dried. According to the preparation method, universality and stability are good, the prepared micro-arc oxidation black thermal control coating on thesurface of the light alloy has high solar high absorbability and emissivity, and the preparation method can be widely applied to high-absorbability and high-emissivity spaceflight thermal control coatings.

Description

technical field [0001] The invention relates to the technical field of metal surface treatment, in particular to a method for preparing a black thermal control coating on the surface of a light alloy. Background technique [0002] Light metals generally refer to metallic materials with a relative density less than 5. They are divided into non-ferrous light metals and rare light metals. Non-ferrous light metals include aluminum, magnesium, calcium, titanium, potassium, strontium, barium, etc. Rare light metals include lithium, beryllium, rubidium, cesium, etc., among which Aluminum, magnesium, and titanium are rich in resources due to their low relative density and high strength (in the earth's crust, the contents of aluminum, magnesium, and titanium are 8.0%, 2.5%, and 0.61%, respectively, accounting for the first and third in the reserves of metal elements , 4 digits), excellent overall performance and other characteristics as lightweight structural materials (mainly referr...

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Problems solved by technology

The above reports are based on the process of adding coloring salt additives to the basic electrolyte, and through the regulation of electrical parameters within a certain range, the black ceramic layer of micro-arc oxidation has been obtained on the surface of a specific substrate, but there is a problem that the preparation process is narrow in scope, that is, A micro-arc oxidation process can only obtain a black ceramic layer on the surface of a specific substrate. This is mainly due to the differences in the chemical activity of light alloys such as aluminum, magnesium, and titanium and the reaction mechanism of micro-arc oxidation, resulting in a black surface of the light alloy. The preparation process of thermal control coating is cumbersome and unique, which is extremely unfavorable for the application of lightweight structural materials

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