钢基表面热镀锌镁合金镀层及其耐蚀性能研究

Hot-dip Zn-Mg Alloy Coating on Steel and Its Corrosion Resistance

采用电解活化助镀剂法在A3钢基表面制得了镁含量为0.3%～2.0%(质量分数,下同)的热镀锌镁合金镀层,对各种成分的锌镁合金镀层进行了电化学测试和中性盐雾实验,并通过电子扫描显微镜观察了镀层的表面形貌.结果表明,在镁含量小于2%的范围内,随着镁含量的增大,热镀锌镁合金镀层的耐蚀性能逐渐提高,但提高的幅度逐渐降低;随着镁含量的增大,镀层晶粒不断细化,组织结构趋于均匀;镁元素主要分布于晶界,起到细化晶粒的作用.

For acquiring new alloy coating with good corrosion resistance and production cost equivalence with hot dip zinc coating, the hot-dip Zn-Mg alloy coating of containing 0.3%~2.0% Mg on surface of A3 steel have been prepared by the method of electrolysis-activated auxiliary. Electrochemistry and neutral salt spray testing have been done for Zn-Mg alloy coating of various components and the surface appearance of coating is observed by SEM. The results show that the corrosion resistance of hot-dipped Zn-Mg alloy coating is improved gradually with increase of the content of Mg, but the increase degree decreases, at the same time, coating crystal particles diminish and structure tends to uniformity. Mg is mainly dispersed to crystal interface for diminishing crystal particles.