复合硅烷/锌涂层耐腐蚀性能的研究

摘要

The hydrolysis process of silane was monitored by a on-line conductivity monitor. The hydrolysis time was determined as 3 h for KH560 and 12 h for silane/zinc composite solutions with different mass fractions of flake zinc powder. A silane/zinc composite coating was prepared by coating the hydrolyzed silane/zinc composite solution on mild steel surface. The corrosion resistance of the composite coatings with different contents of zinc powders was examined by salt spray test, polarization curve measurement, and AC impedance spectroscopy. The section morphologies of the coatings were observed by scanning electron microscopy. The anticorrosion mechanism of silane/zinc composite coating was discussed. The results showed that the corrosion resistance of silane/zinc composite coating is improved with increasing content of zinc powder, and reaches the best when the content of flake zinc powders is up to 45%. The coating obtained therewith endured 576 h in neutral salt spray test, which was 12 times that of the coating without zinc powder. The flake zinc powders form a compact network structure by superposing parallel, leading to slower pass of corrosion media to metal substrate, thus remarkably improving the corrosion resistance.%通过电导率监视仪对硅烷的水解过程进行监控，确定了KH560的水解时间为3 h，含不同质量分数鳞片锌粉的硅烷/锌复合液的水解时间为12 h。将硅烷/锌水解液涂覆到低碳钢表面，制备了复合硅烷/锌涂层。通过盐雾试验、极化曲线和交流阻抗谱研究了不同锌粉含量的硅烷/锌复合涂层的耐蚀性能，通过扫描电镜观察了涂层的截面形貌，探讨了硅烷/锌复合涂层的耐蚀机理。结果表明，复合硅烷/锌涂层的耐蚀性能随着锌粉含量的增加而提高，鳞片锌粉的最大添加量为45%。此含量下的复合硅烷/锌涂层的耐蚀性能最好，中性盐雾时间达576 h，是纯硅烷涂层的12倍。在此硅烷/锌复合涂层中，鳞片锌粉以平行叠加的方式组成致密的网状结构，从而延长了腐蚀性介质到达金属基材的时间，使涂层的耐蚀性能得到明显提高。