A kind of preparation method of thermal control coating on aluminum alloy surface

Abstract

The invention discloses a method for preparing a thermal control coating on the surface of an aluminum alloy, which specifically includes the following steps: first, mechanically polish the aluminum alloy on sandpaper (from 800# to 2500#), wash it with deionized water, and wash it at 1mol Alkali washing in / L NaOH solution for 1-2min, rinse with deionized water, then pickle in dilute sulfuric acid for 2-3min, rinse with deionized water, and finally place in electrolytic solution for anodic oxidation, one-step preparation of high emissivity The thermal control coating is then washed with water and dried to obtain a high-emissivity aluminum alloy thermal control coating. The electrolytic solution includes: H 2 SO 4 (volume fraction 5‑25%), H 3 BO 3 (10‑50g / L), C 7 h 6 o 6 S (20-80g / L), ferrous sulfate (1-5g / L); the technical scheme of the present invention is simple to operate, clean and environmentally friendly, suitable for A2024 aluminum alloy materials and workpieces of various shapes, and easy to industrialize.

Description

technical field [0001] The invention relates to the technical field of metal surface treatment, in particular to a method for preparing a thermal control coating on the surface of an aluminum alloy. Background technique [0002] Due to its light weight, high specific strength, and unique electromagnetic properties, aluminum alloys are widely used in new fields such as aerospace and electronic equipment, especially for electronic casing packaging of spacecraft. With the development of space spacecraft technology, temperature control has become more and more important. The spacecraft experiences extreme temperature cycles in space orbit, which will cause the surface temperature of the spacecraft to vary greatly, and the temperature varies between -200 and +200°C . In the absence of an atmosphere, the heat exchange between the spacecraft and the external environment is limited to radiation, especially the coupling effect of radiation on the outer surface of the spacecraft and ...

AI Technical Summary

Problems solved by technology

Thermal control coatings play an important role in spacecraft components by providing suitable optical properties. Currently used high-emissivity thermal control coatings include two types, one is coated on aluminum with black dye black pigment after anodizing Paint-type thermal control coating on the surface of the alloy, but due to uneven dyeing of organic matter and poor color fastness, it is not suitable for space applications, and the coating has poor adhesion and is easy to fall off, and the solar light absorption rate and infrared emission rate are not high; One is the micro-arc oxidation technology, which is a surface treatment technology developed on the basis of ordinary anodic oxidation. The use of micro-arc oxidation technology can produce thicker aluminum alloy surface, better bonding with the substrate, and has a relatively high High-hardness ceramic oxide film, however, the color of aluminum alloy micro-arc oxidation ceramic coating is usually off-white, while for hard aluminum alloy, due to the copper element in the alloy, the coating is usually gray-brown, resulting in low light reflectivity At the same time, the energy consumption of micro-arc oxidation technology is relatively large, which is not conducive to industrial production

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