在乙醇水溶液中,用硅烷偶联剂 KH560 对纳米 SiO₂ 进行表面改性处理,通过测定粒径,探讨了纳米 SiO₂ 含量、乙醇水溶液配比以及改性剂含量对分散性的影响。 将改性后的纳米 SiO₂ 分散液、水性聚氨酯树脂及无机组分等复配成无铬钝化液,在热镀锌板上制备钝化膜,通过电化学 Tafel 极化曲线、交流阻抗以及中性盐雾试验对比纳米 SiO₂ 改性聚氨酯复合钝化膜和未改性聚氨酯复合钝化膜的耐蚀性,结果表明,与后者相比,前者的耐腐蚀性能有了较大的提升。

In aqueous ethanol solution, the surface of nano-SiO₂ was modified by silane coupling agent KH560 . And the particle sizes were measured. The effects of nano-SiO₂ content, alcohol percentages and the modification agents on dispersity were discussed. The chromium-free passivation solution was made from the modified nano-SiO₂ dispersions, water polyurethane resin and inorganic constituent compound, and it may be coated on the hot galvanized sheet . Corrosion resistances of nano-SiO₂ modified polyurethane composite passivation film and unmodified polyurethane composite passivation film were characterized by the electrochemical Tafel polarization curves, AC impedances ( EIS) and the neutral salt spray tests. The results may show that compared with the latter the former corrosion resistance have been greatly improved.