镍镉热扩散镀层盐雾试验不合格原因分析与排除

Analysis and elimination of unqualified reasons for salt spray test of Ni-Cd thermal diffusion coating

针对一例镍镉热扩散镀层盐雾试验不合格问题,对电镀过程和试验过程所涉及的基体、镀层、外界环境等因素进行逐一分析和排查。结果显示,导致镍镉热扩散镀层盐雾试验不合格的原因是镀层的局部脱落和镀层孔隙。通过采取如下改进措施解决了该问题:一是采用工艺规定下限电流密度电镀;二是增加电镀过程对试片的晃动频次;三是将盐雾试验试片四周打蜡绝缘;四是严禁赤手触摸试片。

In view of a case of unqualified salt spray test of Ni-Cd thermal diffusion coating,the factors such as substrate,coating and external environment involved in the electroplating process and test process were analyzed and checked one by one.The results show that the reasons for the disqualification of the salt spray test of the Ni-Cd thermal diffusion coating are the local peeling of the coating and the coating porosity.The following improvement measures were taken to solve the problem:(1)Electroplate with the lower current density specified by the process;(2)Increase the shaking frequency of the test piece during the electroplating process;(3)Wax and insulate the salt spray test specimen around;(4)Do not touch the test piece with bare hands.