超/特高压直流输电工作环境中纯铜部件点蚀行为

Pitting corrosion behavior of pure copper components in EHV/UHV DC transmission environment

超/特高压输电是实现全球能源互联的核心技术。作为应用最广泛的输电系统导体材料,铜及铜合金的耐蚀性被重点关注。在超/特高压直流输电过程中,周围环境存在较大磁场,导致铜部件的服役环境与普通输电环境不同。采用动电位极化、电化学阻抗谱和元素分析等方法对纯铜在超/特高压环境下的电化学腐蚀行为进行了研究。结果表明:在超/特高压环境下,纯铜在3.5%NaCl溶液(质量分数)中的极限扩散电流高于无磁场条件下的极限扩散电流,并且无磁场条件下的反应电阻比施加了0.1 T磁场条件下的反应电阻明显提高。结合电化学阻抗谱、X射线衍射及元素分析可知,0.1 T磁场会使纯铜的耐蚀性降低,主要腐蚀产物为氧化亚铜。

EHV/UHV power transmission is the core technology to realize the global energy interconnection.As the most widely used conductor materials in power transmission system,the corrosion resistance of copper and copper alloys has been paid more attention.In the process of EHV/UHV DC transmission,there is a large magnetic field in the surrounding environment,which leads to the service environment of the copper components different from that of the ordinary transmission environment.The electrochemical corrosion behavior of the pure copper under the EHV/UHV environment was studied by potential polarization,electrochemical impedance spectroscopy,and element analysis in this paper.The results show that,the limiting diffusion current of the pure copper in 3.5%NaCl solution(mass fraction)under the UHV/UHV environment is larger than that without magnetic field,and the reaction resistance without magnetic field is significantly increased compared with that under 0.1 T magnetic.Combined with the results of electrochemical impedance spectroscopy,X-ray diffraction,and elemental analysis,it is shown that the high-intensity magnetic field(0.1 T)can reduce the corrosion resistance of the pure copper,and the main corrosion product is Cu_(2)O.