弹条渗锌涂层耐蚀性研究

Corrosion resistance of zinc diffusion coating on clip

[目的]研究弹条渗锌层、渗锌+硅酸盐封闭层及渗锌+油性漆封闭层在中性盐雾和二氧化硫环境下的耐蚀性。[方法]借助磁阻法测厚仪和金相显微镜筛选出不同厚度和形貌的渗锌层,然后分别进行硅酸盐封闭和油性漆封闭处理,采用扫描电镜和能谱仪分别观察封闭层分布情况和分析化学成分,最后进行中性盐雾和二氧化硫试验。[结果]硅酸盐封闭层以渗透于间隙的方式分布于渗锌层表层,较薄;油性漆封闭层以一种较为均匀且连续的方式覆盖于渗锌层表层之上,较厚。经120 h中性盐雾和二氧化硫试验后,渗锌层和渗锌+硅酸盐封闭层都有红锈生成,但后者的红锈程度较低,而渗锌+油性漆封闭层未出现红锈。[结论]渗锌层在增加硅酸盐封闭或油性漆封闭后,耐蚀性得到提升,虽然渗锌+油性漆封闭层的耐蚀效果最优,但应结合工艺、环保、安全、成本、产品使用条件等方面更为合理地选取防腐方式。

[Introduction]The corrosion resistance of clips treated by sherardizing,sherardizing+silicate sealing,and sherardizing+oil-based painting in neutral salt spray and sulfur dioxide environments is worth studying.[Method]The sherardizing layers with different thicknesses and morphologies were collected by using magnetoresistive thickness gauge and metallographic microscope,and then sealed with silicate and oil-based paint,respectively.The distribution and chemical composition of the sealing layers were examined by scanning electron microscopy and energy-dispersive spectroscopy.The neutral salt spray test and sulfur dioxide test were carried out.[Result]The silicate sealing layer,which was thin,was distributed on the surface of the sherardizing layer in the way of infiltration into the gaps.The oil-based painting layer,which was thick,was covered on the surface of the sherardizing layer in a more uniform and continuous way.After 120 hours of neutral salt spray test or sulfur dioxide test,red rust appeared on the unsealed and silicate-sealed sherardizing specimens,but the red rust area of the latter was less than that of the former.No red rust was formed on the sherardizing specimen sealed with oil-based paint.[Conclusion]The corrosion resistance of sherardizing layer can be improved by silicate sealing or oil-based painting as a post-treatment.Although the anticorrosion performance of oil-based painting is the best,the post treatment for sherardized products should be selected more reasonably in terms of operation,environmental friendliness,safety,cost,and service conditions.