适用于航空航天零部件的氯化钾镀锌工艺

Zinc electroplating process based on a potassium chloride bath for aerospace components

介绍了一种适用于航空航天零部件的氯化钾镀锌新工艺,包括在钢铁基体从内到外依次制备氯化钾镀锌层、铬酸盐低铬彩色钝化层和羟基石墨烯封闭层。这种新工艺制备的镀层在中性盐雾测试480h内,表面无白色腐蚀产物生成,其耐蚀性远远高于行业标准的要求;在除氢过程中表面无损伤,克服了无氰碱性镀锌不适宜除氢处理的技术缺陷。新型氯化钾镀锌的电流效率明显高于无氰碱性镀锌,向基体中渗氢的倾向低,因此更适用于制备航空航天零部件的防护层。

A novel potassium chloride based zinc electroplating process for aerospace components made of steel was introduced.A zinc coating,a low-chromium iridescent chromate passivation coating,and a hydroxylated graphene sealing layer are formed successively on the steel substrate.The coating with such structure is able to endure 480 hours of neutral salt spray test without the formation of white corrosion product on its surface,showing a much higher corrosion resistance than the requirement of industrial standard.There is no surface damage for the coating prepared by the novel process during hydrogen removal.Hence,the novel process overcomes the shortcoming of cyanide-free alkaline zinc electroplating process which is not suitable for hydrogen removal as a post-treatment.The permeation of hydrogen into the matrix is reduced during the potassium chloride based zinc electroplating process due to it has much higher current efficiency as compared with the cyanide-free alkaline zinc electroplating process.The novel potassium chloride based zinc electroplating process is more suitable for preparing protective coatings on aerospace components.