车身钢板及不同电泳膜厚对耐蚀性的影响研究

Research on Influence of Automobile Body Sheet and Electrophoresis Film Thickness on Corrosion Resistance

模拟车身内腔电泳情况,在普通钢板和镀锌钢板两种材料表面电泳4种不同膜厚涂层进行中性盐雾试验。采用扫描电镜等分析手段,探讨锈蚀产生的过程、原因和规律。试验结果表明:电泳涂膜的耐水性、耐盐雾性一般,已发生穿透腐蚀;在涂膜破损的情况下,涂膜厚度增加对阻止破损处锈蚀蔓延的作用不大;在涂膜完好的情况下,涂膜厚度增加,屏蔽作用加强,防锈效果显著;普通钢板试样腐蚀以点蚀形式进行,镀锌钢板试样腐蚀以全面腐蚀形式进行,普通钢板试样更易出现锈穿现象。

Simulating the electrophoretic situation of automobile inner cavity, neutral salt spray tests were carried out on common steel plate and galvanized steel plate with four different film thickness. The process, cause and regulation of corrosion were discussed through scanning election microscope and other analysis methods. The results showed that water tolerance and salt fog resistance of electrophoretic film was ordinary, through corrosion was showed. With film damage, the increasing of film thickness had little effect on protecting the spread of corrosion. With undamaged film, increasing the film thickness, the stronger shielding effect had, the better anticorrosion effect was showed. The common steel plate showed pitting corrosion characteristic, and the galvanized steel plate showed comprehensive corrosion, through corrosion was more easily showed on common steel plate.