A3钢表面脉冲电沉积锌薄膜的耐蚀性能

选择不同的镀Zn体系，用脉冲电流在A3钢表面电镀Zn薄膜。通过人造海水浸泡，研究锌镀层的耐蚀性能，用SEM，XRD研究锌镀层的形貌和晶面取向。结果表明，钠盐、铵盐、硫酸盐体系制备的镀层钝化后，腐蚀速率明显下降，镀层耐蚀性增强。加入添加剂的碱性锌酸盐镀层钝化后，表面出现裂纹，镀层耐蚀性降低。铵盐体系加入镧盐后镀层耐腐蚀性增强，钠盐、硫酸盐体系加入镧盐后镀层耐腐蚀性降低。加入镧盐后，不改变锌沉积的晶面择优取向，但影响各晶面的织构系数、晶粒尺寸和锌镀层的耐蚀性能。

Corrosion Resistance Performance of Zinc Coating on A3 Steel by Pulse Current Electrodeposition

The zinc coatings on the surface of A3 steel substrate is prepared by pulse electrodeposition m various electrolytes. The corrosion resistance of the zinc coatings is investigated by immersion in the artificial seawater in room temperature, and the surface morphology and zinc deposit preferred orientation of the coating are presented by Scanning Electron Microscopy and X-ray Diffraction. The results show that the corrosion resistance of the zinc deposits prepared in systems of sodium, ammonium zincate, and zinc sulfate are significantly improved after the passivation, corrosion rate is decreased and corrosion resistance is increased. The addition of the RE to the alkaline zincate makes the crack appear on the coatings, and corrosion resistance decrease. The corrosion resistance of the coating is increased by addition of lanthanum in ammonium zincate system, but decreased for sodium zincate and zinc sulfate systems. The addition of the RE to the bath does not change the preferred orientation of deposited Zn, but influence the texture coefficient of low-index crystallographic planes and grain size, and corrosion resistance of the coating.