热镀锌钢板表面硅烷预处理对粉末涂层附着力及耐蚀性的影响

Effect of Silane Pretreatment on Adhesion and Corrosion Resistance of Powder Coating on Hot Galvanized Steel Sheet

为了取代对环境有污染的磷化和铬酸盐钝化工艺,用硅烷对热镀锌钢板预处理后,再涂敷环氧树脂粉末层(Zn/Si/Ep)。通过划格法研究了涂层与基体的结合力,以盐雾腐蚀试验、极化曲线、交流阻抗技术研究了涂层的耐腐蚀性能。结果表明:Zn/Si/Ep具有良好的附着力,且高于磷化环氧树脂粉末层(Zn/P/Ep),耐盐雾腐蚀达到500 h,腐蚀电流密度为3.379×10-7A/cm2;硅烷处理工艺有望取代磷化工艺。

Galvanized steel sheet was pretreated with silane and coated with powder-doped epoxy resin(Zn-Si-EP).The adhesion of the Zn-Si-EP coating to steel substrate was estimated by conducting cross-cut test,and its corrosion resistance was evaluated based on neutral salt spray test as well as polarization curve and electrochemical impedance spectrum measurement.Results show that Zn-Si-EP coating has better adhesion to the substrate than the Zn-P-EP coating.Namely,Zn-Si-EP coating could endure salt spray up to 500 h and had a corrosion current density of 3.379×10-7 A/cm2.In general,the process of pretreatment with silane may be used to replace phosphating process for galvanized steel.