无铬锌铝涂料配方工艺研究

【作者】 娄萃；

【导师】 蔡晓兰；

【作者基本信息】 昆明理工大学 ， 有色金属冶金， 2007， 硕士

【摘要】 随着全球环保意识的日益加强，具有污染性的的含铬达克罗涂料的发展空间越来越小，但由于达克罗工艺具有优异的防腐性能，因此本文就是在达克罗的基础上研究不含铬的锌铝涂料。本文首先介绍了该技术的起源、发展、研究现状、发展预测以及膜层的特点、应用；其次介绍了实验用的材料、设备及实验工艺流程，并对膜层性能介绍了相应的检测方法；再者介绍了涂液的主要组成、操作条件对涂层性能的影响；最后通过扫描电镜(SEM)、电子能谱(EDS)对膜层的结构、元素组成进行了分析，并对膜层的成膜机理、防腐机理作了初步的探讨。所得到的实验结果如下：1．通过对实验的主要原料锌粉、铝粉的形状、用量作的讨论，发现片状粉耐蚀性优于球状粉，确定采用片状金属粉，考虑到涂液的粘稠度，涂层的耐蚀性、附着力等性能，最终将锌粉的含量控制在200～320 g／L为佳。同时为了得到较好的涂层外观并增加其耐蚀性，将铝粉含量控制在40～200 g／L之间。2．考虑到金属粉的在涂液中的分散性及烘烤时溶剂的完全挥发程度，采用混合型溶剂，溶剂配比为：二甲苯：A％；正丁醇：B％；乙酸乙酯：C％。3．实验采用的粘结剂为环氧树脂与硅烷的结合，得到的涂层具有较好的附着力、耐蚀性，其用量定为环氧树脂：A g／L；硅烷：B g／L。4．实验通过对烘烤温度、时间及搅拌时间的讨论，即将烘烤和搅拌条件规定如下：预烘温度为120～150℃，时间25～30min，烧结固化温度为300±10℃，时间30min；搅拌时间：4～6h。5．实验得到的锌铝涂层为银白色，具有金属光泽，耐硝酸氨腐蚀实验平均达100分钟，耐盐雾试验达1000小时无锈，结合力好，完全无铬，符合环保要求。6．实验通过扫描电镜及能谱分析，对其表面形貌及成分作了分析，推断出膜层的成膜机理和防腐机理，防腐主要是以下几种方式：结构上的屏蔽效应；锌铝作为阳极被消耗，保护了铁基体；锌铝氧化物的钝化作用所组成。更多还原

【Abstract】 With the whole environmental protection consciousness gradually enhancement, has pollutional chromium of dacroment coating the development space getting smaller. Because the dacroment handicraft has the outstanding corrosion resistance, therefore the main body of the article is studying the zinc aluminium coating of not containing chromium on dacroment’ s basis.This article first introduced this technical origin, the development, the research present situation, the development forecast as well as the film characteristic, the application. Second introduced the experimental material, the equipment and the experiment technical process, and introduced the corresponding examination method to the film performance. Third introduced the compositions of coating solution and the operating condition to the coating performance influence. Finally, the structure of the coat and the element composition have been analyzed, meanwhile the mechanism of coating formation and corrosion resistance have been discussed preliminary by using SEM, EDS. The results as follows:1.By discussion that raw material zinc powder, aluminum powder’ s form and amount, the corrosion resistance of coat prepared with flake powder was better than that prepared with grainy powder which was found. So the flake powder was used. The stickiness of coating solution, the corrosion resistance and adhesion of coat were considered, the zinc powdercontents is controlled ultimately in 200 - 320g/L. At the same time, for getting fairly good coating outward appearance and increasing the corrosion resistance,aluminum powder contents is controlled between 40-200g/L.2. Considered the metal powder’ s dispersivity in coating solution and the solvent complete volatility degree when roasting,used the mixed solvent. The solvent proportion is:Dimethylbenzene:A%; Normal butyl alcohol:B%; Ethyl acetate:C%.3. The cementing agent of the experiment is epoxy resin and the silicon hydride union, the coating which has good adhesion and corrosion resistance. Its amount of used as follows: Epoxy resin:Ag/L;Silicon hydride:Bg/L.4. The experiment through to the temperature, the time of baking and the time of agitating discussion, the condition of baking and agitating as follows: The preliminary baking temperature: 120-150℃,Time:25-30min;The sintered solidification temperature:300±10℃,Time:30min;Stirring time:4-6h.5. The zinc aluminium coating is silver-white color, has the metallic luster. The experiment time of corrosion resistance for ammonium nitrate can reach 120 minutes and 1000 hours for salt fog without appearing rust. Meanwhile, the bond strength between coat and substrate is very well. The coat does not have the chromium completely, conforms to the environmental protestion requirement.6. The superficial appearance and the composition of coating were analysised by using SEM and EDS. Meanwhile, the mechanism of coat formation and corrosion resistance were deduced by using SEM and EDS. The mechansim of corrosion resistance mainly is following several ways:Screening effect of structure; Zinc and aluminum is consumed as the anode;The ferric substrate has been protected;Zinc oxide and aluminium oxide inactivation effect.更多还原