船用辅冷凝器B30合金管腐蚀失效分析

摘要

Early failure happened in large areas of B30 alloy tube used for vessel auxiliary condenser.The failure reasons were analyzed through corrosion morphology,corrosion products and polarization curves.The results indicate that selective corrosion happened to B30 alloy,and the most serious corrosion in local area of inner surface was denickel corrosion because of pitting.The acidic environment in the pitting pits made de-nickel corrosion more serious.Potential of copper is more positive than that of nickel,so copper could deposited on grain boundaries.%某船用辅冷凝器tB30合金管发生了大面积早期失效.通过失效B30合金管的腐蚀形貌、腐蚀产物及极化曲线分析其失效原因.结果表明:B30合金管发生了选择性腐蚀,其内表面局部区域发生的严重腐蚀是由点蚀引起的脱镍腐蚀,点蚀坑内的酸化环境使脱镍腐蚀更加严重;由于铜的电位正于镍的,铜在晶粒边界附近发生回沉积.