中文摘要：

锌镁合金镀层是一种具有优异防腐蚀性能的新型钢板保护镀层，真空镀由于其优良的镀层性能正逐步发展为锌镁合金镀层的重要制备工艺。本文在镀锌钢板表面采用真空热蒸发镀镁，再由快速退火工艺形成锌镁合金镀层。通过X射线衍射、二次离子质谱和扫描电镜分析了在退火过程中锌、镁层的扩散过程，并通过盐雾试验和电化学测试研究扩散过程对锌镁合金镀层腐蚀性能的影响。研究发现：退火过程中镁快速向锌层扩散，并在锌层内一定深度处富集，而锌逐渐向镁层扩散，这种相互扩散形成了锌镁合金。同时铁也会向锌层扩散，形成锌铁合金。镁富集区具有扩散阻挡作用，阻止镁进一步向内扩散的同时也阻止铁向表面的扩散。腐蚀性能测试表明，370℃下退火60-120s的样品具有较好防腐蚀性能。

英文摘要：

The Zn-Mg alloy coatings were grown on the Zn-coated steel substrates by vacuum evaporation of Mg and rapid annealing. The impacts of the alloy film growth conditions on the corrosion resistance were evaluated. The Zn-Mg coatings were characterized with X-ray diffraction, secondary ion mass spectroscopy and scanning electron microscopy. The results show that the inter-diffusion of Zn and Mg strongly affects the microstmctures and corrosion resistance of the alloy coating. In the annealing,Mg rapidly diffused into Zn matrix,accompanied with the formation of the Mg-rich layer inside the Zn coating, and a slow diffusion of Zn into Mg layer. Moreover, the diffusion of Fe into Zn coating resulted in Zn-Fe alloy formation.The Mg-rich layer blocked the diffusion of Mg into Zn and the surface segregation of Fe.The annealing at 370℃ for 60 - 120 s significantly increased the corrosion resistance of Zn-Mg alloy coating.