一次电力设备镀锡铜排变色原因分析

Discoloration Analysis of Tin-plated Copper Bar for Primary Power Equipment

镀锡铜排在一次电力设备中作为载流部件广泛使用,其可靠性关系着一次电力设备的稳定、安全运行。文中介绍了一起年检时(运行5年后)发现的某工程镀锡铜排变色(发黄、发黑)和麻点的案例,结合现场情况和铜排表面状态对变色原因进行分析,并利用扫描电镜(SEM)、能谱分析(EDS)、X射线衍射仪(XRD)和X射线光电子能谱仪(XPS)等手段对变色层进行表征,结果表明镀锡层发黄发黑处成分均为SnO_(2),变色原因为铜排搭接处发热过大和镀锡层缺陷导致的表面氧化腐蚀,并提出了相关改进措施。

Tin-plated copper bar,as the current carrying element,is used widely in primary power equipment.Its reliability is related to the stable and safe operation of the primary power equipment.In this paper,a case of discoloration(yellowing,blackening)and pitting of tinned copper bar in a project discovered during the annual inspection(after 5 years of operation)is introduced.The causes of the discoloration are analyzed in combination with site conditions and surface state of copper bar.The discoloration layer is characterized by means of such means as scanning electron microscope(SEM),energy dispersive spectrometer(EDS),X-ray diffraction(XRD)and X-ray photoelectron spectroscopy(XPS).The results show that the composition at the blackening and yellowing parts of tin plating layer is SnO_(2).The causes of the discoloration are the surface oxidation corrosion due to overheating at the overlap of copper bars and defects of tin plating layer,and the relevant improvement measures are given.