( 1.天津大学 化工学院， 天津 300072；
2. 92854部队， 湛江 524003)
摘 要: 采用金相显微镜、 X射线衍射仪、 扫描电镜结合能谱测试技术研究了紫铜海水管焊接接头部位在海水中的腐蚀特征。结果表明： 采用黄铜焊条的接头部位为α+β双相黄铜， 在海水中发生了严重的不均匀脱锌腐蚀，脱锌后合金表面的颜色由黄变为紫红； 腐蚀产物主要由ZnCl2和ZnSO4等锌盐和锌的氧化物ZnO2和ZnO组成， 此外还含有少量的铜绿Cu3(SO4)(OH)4；采用白铜焊条的接头部位为Cu-Ni-Zn三元单相固溶体(α相)， 在海水中浸泡前后结构未发生变化， 表面较致密、 无明显孔洞和点蚀， 与黄铜焊缝相比， 具有优异的耐海水腐蚀性能。
关键字: 铜合金； 海水管； 焊接； 腐蚀
（1. School of Chemical Engineering and Technology,
Tianjin University, Tianjin 300072, China;
2. The Unit No.92854 of the Chinese People's Liberation Army,
Zhanjiang 524003, China）
Abstract: The corrosion characters of the welded joints of copper pipe in seawater were analyzed by metallurgical microscope, scanning electron microscopy (SEM), X-ray diffractometry (XRD) and energy dispersive X-ray analysis-(EDX). The results indicate that the metallographic structure of welded joint formed by brass welding rod is (α+β) phase brasses. The brass-welded joint was corroded seriously in seawater because of dezincification, then the surface color of the alloy changes from yellowish to purple. The XRD analysis show that the corrosion products are ZnCl2, ZnSO4, ZnO2, ZnO and a small amount of Cu3(SO4)(OH)4. And the metallographic structure of welded joint formed by cupronickel welding rod is single α-phase, which is Cu-Ni-Zn solid solution alloy. The structure has no change before and after immersing in seawater, and the surface is fine and has no holes and pitting corrosion. The corrosion resistance of cupronickel-welded joint is better than that of the brass-welded joint.
Key words: copper alloy; seawater pipe; welded joint; corrosion
