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对汽车用锌镁涂层钢的耐腐蚀性进行研究,利用X射线衍射、X射线光电子能谱和扫描电子显微镜表征表面腐蚀产物。结果表明,锌镁涂层钢表面存在西蒙脱石、氢氧化镁和羟基碳酸盐物质。在锌阴极处由于氢氧化镁的沉淀,其氧的还原活性降低,通过吸收大气逐渐转化为更可溶的羟基碳酸酯二氧化碳,这使表面pH充分降低,使不溶性硅溶胶在腐蚀表面上沉淀,使总体耐腐蚀性增强。
The corrosion resistance of automotive Zinc Magnesium coated steel was studied. The surface corrosion products were characterized by X-ray diffraction, X-ray photoelectron spectroscopy and scanning electron microscopy. The results show that there are xanthanum, magnesium hydroxide and hydroxy carbonate on the surface of Zn-Mg coated steel. Due to the precipitation of magnesium hydroxide at the zinc cathode, the oxygen reduction activity is reduced and gradually converted to the more soluble hydroxycarbonate carbon dioxide by absorption of the atmosphere, which lowers the surface pH sufficiently for the insoluble silica sol to precipitate on the etched surface, The overall corrosion resistance increased.