以硅烷为粘接剂、片状锌铝粉为原料,在20钢基体上制备了无铬的环保型锌铝基耐蚀涂层,以替代传统的含铬达克罗涂层;用X射线衍射仪、扫描电子显微镜对涂层的成分和结构进行了表征,用开路电位、电化学阻抗谱测试和盐雾试验研究了涂层的电化学和耐腐蚀性能.结果表明:无铬锌铝基耐蚀涂层的耐蚀性能与达克罗涂层几近相同;硅烷偶联剂在涂层中主要起粘结作用,涂层中片状锌铝粉分布均匀,层层堆叠;涂层对基体具有牺牲阳极保护和屏蔽作用,增加涂层厚度可增强涂层的屏蔽作用.

To replace the traditional chrome dacromet coating,an environmental and chrome-free zinc/aluminum based corrosion resistant coating was prepared on 20 steel using silane as binder and flaky zinc/aluminum powders as raw materials.The composition and structure of the coating were characterized by X-ray diffraction and scanning electron microscopy.The electrochemical behavior and corrosion properties of the coating were investigated by open-circuit potential measurement,electrochemical impedance spectroscopy and salt spray test.The results indicate that the corrosion resistance of the chrome-free coating was nearly the same to that of the traditional chrome dacromet coating.It was also showed that silane only played an adhesive role in the coating and the flaky zinc and aluminum powders were uniformly distributed and stacked in the coating.Cathodic protection and shielding effects were the main means employed to protect the matrix metal against corrosion,and the shielding effect was increased with the increase of the coating thickness.