海南电网刀闸铝合金部件腐蚀失效分析  

Corrosion Failure Analysis on Al-Alloy Parts of Knife Switches in Hainan Power Grid

作　　者：杨大宁 董凯辉 符传福 单大勇[2] 张奇伟 张帆[2] 宋影伟[2] 韩恩厚[2] 

机构地区：[1]海南电力技术研究院,海口570203 [2]中国科学院金属研究所核用材料与安全评价重点实验室,沈阳110016

出　　处：《腐蚀科学与防护技术》2016年第1期82-87,共6页Corrosion Science and Protection Technology

摘　　要：采用金相、SEM、EDS和XRD等方法分析了海南电网刀闸铝合金部件的腐蚀失效原因。结果表明,刀闸杆所采用的挤压态LY12铝合金材料,其基相中含有使得该合金具有较高晶间腐蚀倾向的Cu Al2强化相,且基体材料中存在有可以显著降低合金力学性能的光亮晶粒组织,在晶间腐蚀与应力的协同作用下,产生了较为严重的剥蚀现象;在海岛环境中Cl及工业污染中S的影响下,刀闸底座表面的镀锡层优先脱落,基体外露,但Al及铝合金基体表面自然形成的钝化膜会继续起到腐蚀防护的作用。在海南地区,Al-Cu合金完全不适用,而Al-Si合金可以安全使用。Corrosion failure process of Al- alloy parts of knife switches in Hainan power grid was investigated by means of metalloscope and scanning electron microscopy（SEM） with energy dispersive spectroscopy（EDS） and X- ray diffraction（XRD）. The results show that the material of breaker action bar is as-extruded LY12 Al-alloy, the matrix phase of which contains precipitates of Cu Al2 thereby, with a higher tendency to intergranular corrosion. Certain light grains are observed in the matrix, which may result in dramatic decrease of mechanical properties. Severe exfoliation corrosion is developed due to the synergistic of intergranular corrosion and stress, while the plated tin layer peeled off preferentially by the attack of corrosive substances containing Cl and S from the island environment and industrial pollution, thereby the substrate exposures. Meanwhile, Al and its alloys may still be protected by the oxide scale formed spontaneously on their surface. In general Al-Cu alloys cannot be applied at all, but Al-Si alloys can be used safely in Hainan island.

关 键 词：户外隔离刀闸 LY12铝合金 海岛环境 腐蚀失效 

分 类 号：TG174[金属学及工艺—金属表面处理]