镀锌层硅钛复合钝化工艺

Silicon-Titanium Composite Passivation Process on Zinc Coating

为提高镀锌层硅钛复合钝化膜的耐蚀性能,缩短钝化时间,改善钝化液的稳定性,采用正交试验对镀锌层硅钛复合钝化工艺进行了优化。通过对样品复合钝化膜的Tafel曲线测试、5%Cu SO_4点滴测试和中性盐雾腐蚀测试,研究了硅钛复合钝化工艺参数对钝化膜外观和耐蚀性的影响。结果表明:硅钛复合钝化液的最佳配方及工艺条件为10 g/L Na_2Si O_3·9H_2O,10 g/L Na NO_3,2 m L/L Ti Cl_3,5 m L/L H_2O_2,2 g/L KF,p H=2.0,钝化时间30 s,钝化温度25℃,60℃恒温烘干10 s;本工艺获得的钝化膜中性盐雾试验出白锈时间为72.0 h,与三价铬钝化膜耐蚀性能相当。

Silicon-titanium composite passivation process was optimized by orthogonal experiments.By evaluating the composite passivation films by Tafel polarization curves,5%CuSO_4 dripping test and NSS,the effects of silicontitanium composite passivation process parameters on the appearance and corrosion resistance of the passivation film were investigated.Results showed that the optimum formula was 10 g/L Na_2SiO_3 · 9H_2O,10 g/L NaNO_3,2 mL/L TiCl_3,5 mL/L H_2O_2,and 2 g/L KF under pH =2.0,and the optimum conditions were passivation at 25 ℃ for 30 s,and drying at 60 ℃ for 10 s.Besides,the time of the white rust appeared on the prepared passivation film in the NSS of the process was 72.0 h,which indicated that the corrosion resistance of this film was comparable to that of trivalent chromium passivation film.