纳米SiO_2在电镀锌三价铬钝化中的作用

Function of Nanoscale Silica in the Process of Trivalent Chromium Passivation for Galvanizing Coating

我国镀锌层三价铬钝化膜的性能仍不完善,为了进一步增加钝化膜的耐腐蚀能力,将纳米SiO_2加入到三价铬钝化液中,对电镀锌层进行常温彩色钝化-封闭同步处理。通过中性盐雾试验与电化学极化曲线对钝化膜的抗腐蚀性能进行评价。结果表明:钝化液中纳米SiO_2含量为3.5 g/L时,钝化液稳定,与三价铬共沉积,产生协同作用,钝化膜光亮,镀锌层的耐蚀性能显著提高。

Nanoscale SiO_2 was introduced into trivalent Cr passivation solution to conduct room temperature coloring passivation-simultaneous sealing of galvanizing coating.The corrosion resistance of resultant passivation coating was evaluated by conducting neutral salt-spray test and measuring electrochemical polarization curve.It was found that the trivalent Cr passivation solution containing 3.5 g/L nanoscale SiO_2,had good stability.Nanoscale SiO_2 was co-deposited with trivalent Cr and had synergistic effect with the latter,resulting in significantly improved brightness of the passivation coating and greatly increased corrosion resistance of the galvanizing coating.