镁合金有机复合散热涂层的制备及性能研究

发布时间：2019-01-01 08:24

【摘要】：镁合金是当前最轻的商用金属结构材料,其导热性能仅次于铜和铝,在同时要求轻量化和导热性能的领域具有很好的应用前景,如大型户外灯罩、通讯基站散热部件等。但镁合金耐腐蚀性能差,在工程应用中往往需要采用表面防腐涂层来保证其防腐能力,目前工程上使用最多的是有机涂层,导热性差,不可避免地导致镁合金构件综合散热性能下降,成为镁合金在这些领域推广应用的技术瓶颈之一。针对上述问题,本文通过向有机硅树脂涂层中填充高导热填料,研究填料含量和种类对涂层散热性、耐腐蚀能力及机械性能的影响,旨在为开发散热-防腐性能兼顾的镁合金有机涂层提供理论支撑。本研究以AZ31B镁合金为基板材料,以水性有机硅树脂为涂层基体材料,以纳米铜粉、纳米碳粉、纳米碳化硅为导热填料粒子,制备了17种不同的有机复合涂层,并对有机复合涂层的散热性、机械性能和耐腐蚀性进行测试表征,并进行综合技术性能评估。主要研究结果如下:①当填料较少时并不能提高有机硅树脂涂层的散热性,只有超过一定含量才有明显的效果,对于同一种填料,随着其含量的增加,涂层散热效果越来越好,但是涂层散热性与填料含量并没有表现出线性关系。当填料含量相同时,纳米铜粉对有机硅树脂涂层散热性的影响最为明显,其效果优于纳米碳粉和纳米碳化硅。当填料粒子含量相同时,混杂填料对有机硅树脂涂层散热性的影响优于单一填料。②填料能够提高有机硅树脂涂层的硬度和耐冲击性,随着填料含量增加有机硅树脂涂层硬度越来越高,但是涂层的耐冲击性随填料粒子含量先上升后下降,填料含量相同时,添加铜粉的有机硅树脂涂层的硬度最高,耐冲击性最好,添加碳化硅的有机硅树脂涂层的硬度最低,耐冲击性最差。对于附着力,填料种类和含量对有机硅树脂涂层几乎没有明显的影响,即填料并没有恶化涂层的附着力③纳米碳化硅和纳米碳粉提高了有机硅树脂涂层的耐腐蚀性,纳米铜粉降低了有机硅树脂涂层的耐腐蚀性。此外,可以发现当添加同种导热填料粒子时,有机复合涂层的耐盐雾腐蚀性随着填料含量的增加而降低。当进行30小时盐雾腐蚀时,涂层表面腐蚀都很严重,其中添加纳米碳粉和碳化硅的有机复合涂层表面的鼓泡现象都很严重,腐蚀面积很大,添加纳米铜粉粒子的有机复合涂层表面生产很厚一层疏松的腐蚀物,其腐蚀程度最严重。④对于同一种填料,当填料粒子含量0-60份时,涂层的综合技术性能越来越好。当填料含量相同时,纳米铜粉对有机硅树脂涂层综合技术性能的提升最为明显,其效果优于纳米碳粉和纳米碳化硅。当填料粒子含量相同时,添加三种混杂的有机复合涂层综合技术性能最好。
[Abstract]:Magnesium alloy is the lightest commercial metal structure material at present, and its thermal conductivity is second only to copper and aluminum. Magnesium alloy has a good application prospect in the field of both lightweight and thermal conductivity, such as large outdoor lampshade, communication base station heat dissipation parts and so on. However, the corrosion resistance of magnesium alloy is poor, so it is necessary to use surface anticorrosive coating to ensure its anticorrosion ability in engineering application. At present, organic coating is the most used in engineering, and its thermal conductivity is poor. It inevitably leads to the deterioration of the comprehensive heat dissipation of magnesium alloy components and becomes one of the technical bottlenecks in the popularization and application of magnesium alloys in these fields. In order to solve the above problems, the effect of filler content and type on the heat dissipation, corrosion resistance and mechanical properties of the coating was studied by filling the coating with high thermal conductivity. The purpose of this paper is to provide theoretical support for the development of organic coatings of magnesium alloys with heat dissipation and anticorrosive properties. In this paper, 17 kinds of organic composite coatings were prepared by using AZ31B magnesium alloy as substrate material, waterborne silicone resin as coating material, nano-copper powder and nano-silicon carbide as thermal conductive filler particles. The heat dissipation, mechanical properties and corrosion resistance of the organic composite coatings were tested and characterized, and the comprehensive technical properties were evaluated. The main results are as follows: 1 when the filler is less, the heat dissipation of the organic silicone resin coating can not be improved, only when the content of the coating exceeds a certain content has obvious effect. For the same kind of filler, with the increase of its content, the heat dissipation effect of the coating becomes better and better. However, there is no linear relationship between coating heat dissipation and filler content. When the filler content is the same, the effect of nano-copper powder on the heat dissipation of organic silicone resin coating is the most obvious, and the effect is better than that of nano-carbon powder and nano-silicon carbide. When the content of filler particles is the same, the influence of hybrid filler on heat dissipation of organic silicone resin coating is better than that of single filler. 2 packing can improve the hardness and impact resistance of organic silicone resin coating. With the increase of filler content, the hardness of organic silicone resin coating is higher and higher, but the impact resistance of the coating increases first and then decreases with the content of filler particles. When the filler content is the same, the hardness of organic silicone resin coating added with copper powder is the highest. The impact resistance is the best and the hardness is the lowest and the impact resistance is the worst. For adhesion, the type and content of fillers had little effect on the coating of silicone resin, that is, the adhesion of the coating was not aggravated by the filler. 3 nanometer silicon carbide and nano carbon powder improved the corrosion resistance of the coating. Nano copper powder reduces the corrosion resistance of silicone coating. In addition, it can be found that the corrosion resistance of organic composite coatings decreases with the increase of filler content when the same thermal conductive filler particles are added. After 30 hours of salt spray corrosion, the corrosion on the coating surface is very serious, and the blistering phenomenon on the surface of organic composite coating with nano-carbon powder and silicon carbide is very serious, and the corrosion area is very large. The surface of organic composite coating with nano-copper powder particles produces a thick layer of loose corrosion, and its corrosion degree is the most serious. 4 for the same filler, when the filler particle content is 0-60 phr, the comprehensive technical properties of the coating become better and better. When the filler content is the same, the comprehensive technical properties of organic silicone resin coating are improved most obviously by nano-copper powder, and the effect is better than that of nano-carbon powder and nano-silicon carbide. When the content of filler particles is the same, adding three kinds of hybrid organic composite coatings has the best comprehensive technical properties.
【学位授予单位】：重庆大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TG174.4

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