目的：研究老旧高压输电耐张线夹内部交流腐蚀。方法截取已运行35 a的耐张线夹并解剖,采用扫描电子显微镜分析腐蚀区的微观形貌,采用X 射线衍射仪、能谱仪和X射线光电子能谱仪对腐蚀区元素及物相进行分析鉴定,分析线夹内部腐蚀损伤演化过程。结果线夹内表面与铝线表面局部出现大量白色腐蚀产物和黑色覆盖物,白色腐蚀物呈粉末和片层两种形态。分析表明,腐蚀产物相组成为Al2 O3,AlO( OH)和AlOOH；黑色覆盖物随深度增加而减少,黑色区域主要元素为Al,O和C,物相组成为Al2 O3,C( graphite)和含C有机物。钢芯锌层破坏区的内层铝线更易腐蚀,腐蚀区呈灰黑色,微观形貌为富铁元素颗粒镶嵌在其它腐蚀产物中,区域的主要元素为Al,C,O,Fe和Zn,Fe元素存在形式为Fe2 O3；钢芯表面镀锌层局部腐蚀严重,呈现平面型点蚀形貌,主要元素为Zn,Al,C和O,Zn腐蚀产物为六边纤锌矿结构ZnO。结论内部交流腐蚀原因为液体渗入,同时腐蚀产生大量的热致使材料分解。
Objective To study the internal AC corrosion of old strain clamp. Methods The strain clamp which has been run for 36 years was cut and dissected. Scanning electron microscope( SEM) , X-Ray diffraction ( XRD) and X-ray photoelectron spectros-copy ( XPS) were used to observe and analyze the microstructure, elements and corrosion products in order to explore the evolution of internal corrosion damage of strain clamps. Results Lots of white corrosion product and black covering occurred on the inner sur-face of strain clamp and surface of aluminum conductor. White corrosion product presented two forms, powder and slice. The prod-uct consisted of Al2 O3 , AlO( OH) and AlOOH. The black covering reduced with increasing depth. The main elements were Al, O and C, and the phases were Al2 O3 , Carbon ( graphite) and organic compounds. The aluminum conductor was corroded more seri-ously near the steel core where the Zn protective layer was damaged. The corrosion region was black. There were some iron-rich particles embedded in other corrosion products. The main elements were Al, C, O, Fe and Zn in the corrosion region, and the ex-isting form of Fe element was Fe2 O3 . The local corrosion of the surface of the steel core was serious. It exhibited a planar pitting morphology. The main elements were Zn, Al, C and O, and the corrosion product of Zn was hexagonal wurtzite ZnO. Conclusion Liquid entering into strain clamp resulted in serious internal AC corrosion and produced a lot of heat, which decomposed the seal material.
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