添加表面活性剂和亚铁盐助镀对热浸镀锌层耐蚀性能的影响

Effect of Surfactants and Ferrous Salt Additive on Corrosion Resistance of Hot-Dip Galvanized Coating

针对批量热浸镀锌传统氯化锌+氯化铵复盐助镀过程的氨氮烟尘污染问题,采用常用无机盐、稀土盐,添加3类表面活性剂和亚铁盐配制了系列无铵助镀液,采用电化学极化法和全浸试验法测试了系列无铵助镀液处理基础上所获得热浸镀锌层的耐腐蚀性能,分析了助镀剂中表面活性剂及亚铁盐对热浸镀锌层耐蚀性能的影响,采用金相显微镜观察分析了无铵助镀条件下镀层的组织结构。结果表明:在电化学和全浸试验中单纯加入表面活性剂时,镀层的耐蚀性有所降低,但通过在无铵助镀剂中加入一定量的亚铁盐可提高镀层的耐蚀性,其中FC09-Ⅱ系列中添加10 g/L亚铁盐、FC-3c系列中添加10 g/L亚铁盐、FC-3d系列中加入20 g/L亚铁盐得到的热浸镀锌层耐腐蚀性较好。

A series of ammonium-free fluxes were synthesized by using inorganic salts and rare-earth salts as main components,and 3 kinds of surfactant and ferrous salt as additives.The electrochemical polarization method and total-immersion test were used to study the corrosion resistance of hot-dip galvanized coating obtained by adding a series of ammonium-free fluxes,and the influences of surfactants and ferrous salt in fluxes on the corrosion resistance of hot-dip galvanized coating.Moreover,the organization structure of coating under ammonium-free fluxes conditions was analyzed by metallurgical microscope.Results showed that with adding surfactant only,the corrosion resistance of coating was reduced during electrochemical test and total-immersion test.Meanwhile,adding a certain content of ferrous salt in ammonium-free fluxes could improve the corrosion resistance of coating.With adding 10 g/L ferrous salt in FC09-Ⅱ series,10 g/L in FC-3c series,20 g/L in FC-3d series,the hot-dip galvanized coating had better corrosion resistance.