电气铜排镀锡层的防护性能研究

Research on the Protective Performance of Tinning Layer on Electrical Copper Bars

为进一步促进电镀锡工艺在电气铜排中的实际应用,采用酸性镀锡工艺在铜排表面制备不同厚度的镀锡层,系统性研究了不同锡层厚度和不同锡保护剂对外观、接触电阻、可焊接性的影响;并采用电化学扫描、中性盐雾试验和高温高湿试验研究了其耐蚀性能。结果表明:铜排镀锡后接触电阻仅增大0.2μΩ,且锡层厚度对接触电阻影响较小;钎焊覆盖率提高40%,随着锡厚度增加焊接面更加细致;高温高湿和中性盐雾试验通过1000 h测试,无严重腐蚀;锡保护工艺提高镀层防变色、耐腐蚀性能的同时对接触电阻和可焊接性影响较小。最后对不同服役条件下的铜排给出了对应的镀锡防护方案。

In order to further promote the practical application of tin plating process in electrical copper bar,tin coating with different thickness on surface of copper bar was prepared using acid tin plating process,and the influence of tin layer thickness and protective agent on appearance,contact resistance and weldability were systematically studied.Also,the corrosion resistance was studied by electrochemical scanning,neutral salt spray test and high temperature and high humidity test.Results showed that the contact resistance increased by 0.2μΩafter the copper bar was tinned,and the different thickness of tin layer had little effect on it.Increasing the coverage of tin on the welding surface by 40%and the welding surface was more detailed with the increase of tin thickness.After 1000 h of high temperature,high humidity and salt spray test,there was no serous corrosion.On the premise of having little effect on the contact resistance and weldability,the tin protection process improved the anti-tarnishing ability and corrosion resistance of the tin layer.At last,the corresponding tin plating protection scheme of copper bar under different service conditions was given.