| Magnesium alloy is the lightest commercial metal structure material, which thermal performance is second to the copper and aluminum, and has a good application prospect in both the lightweight and thermal conductivity required field simultaneously, such as outdoor lamp, communication base station radiation components etc..But the corrosion resistance of magnesium alloy is poor, which need to use anti-corrosion coating to ensure its anti-corrosion ability in engineering application. The most used is the organic coating with poor thermal conductivity in engineering, which inevitably leads to a decline in the integrated component thermal performance of magnesium alloy and has become one of the technical bottlenecks in the popularization and application of these areas.Focusing On the above problems, the heat resistance, corrosion resistance and mechanical properties of coating influenced by different contents and types by means of filling high thermal conductive fillers to the silicone resin coating were studied, in order to provide theoretical support for the development of heat-corrosion performance of magnesium alloy organic coating.AZ31B magnesium alloy was taken as substrate material in this study, silicone resin with waterborne was taken as coating substrate, and nanometer copper powder, nanometer carbon powder and nanometer silicon carbide were used as thermal conductive filler particles. By these materials, 17 kinds of organic composite coatings were prepared, and heat compensator dispersion, mechanical properties and corrosion resistance of organic composite coating were characterized, and comprehensive technical performance was evaluated. The main results are as follows:① A small quantity of filler can not improve the heat dissipation of the organic resin coating, only over a certain content the filler have significant effect. For the same kind of packing, the heat dissipation effect is better with the content of coating increased, but the coating heat dissipation and filler content did not show a linear relationship. When the filler content is the same, the effect of nanometer copper on the heat radiation of silicone resin coating is the most obvious, which is better than that of nanometer powder and nanometer silicon carbide. When the filler particles content is the same, the influence of hybrid fillers on the heat dissipation of silicone resin coating is better than that of the single filler.② The filler can improve the hardness and impact resistance of silicone resin coating, and the hardness is higher with the filler content increased, but the shock resistance of the coatings increase first and then decrease with the increasing filler content. Silicone resin with copper powder shows the best hardness and impact resistance but by addition of silicon carbide, silicon resin coating demonstrates the lowest hardness and impact resistance. For, filler type and content has no obvious influence on the adhesion of silicone resin coating, which means the filler has no deterioration of the adhesion of the coating.③ Nano-silicon carbide and carbon nano silicone resin coating improved the corrosion resistance of copper nanoparticles but reduced the silicone resin coating corrosion resistance.In addition,organic composite coating spray corrosion resistance increased with filler content decreased when the same kind of thermally conductive filler particles were added.When the 30 hours salt fog corrosion test was performed, the corrosion of the coating surface is very serious, the surface of organic composite coating added by nanometer powder and silicon carbide shows serious drum bubble phenomenon, and the corrosion area is large. The surface of organic composite coating with the addition of nanometer copper particle forms a thick layer of loose corrosion products, which causes the most serious corrosion phenomenon.④ For the same kind of packing, the technical performance of coating is better with the increase of filler content. When the filler content is the same, the influence of technical performance of nanometer copper on silicone resin is the most obvious, which is better than that of nanometer carbon powder and nanometer silicon carbide. When the filler particle content is the same, the organic composite coating added by three kinds of mixed filler particles shows the best technical performance. |
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