稀土对Cu-Ni-Al合金耐冲刷腐蚀性能的影响

在冲蚀试验机上模拟了耐蚀Cu-Ni-Al合金在人工海水冲刷作用下的腐蚀情况,分析了不同冲刷时间、不同海水流速下Cu-Ni-Al合金的腐蚀行为,重点研究了稀土元素对Cu-Ni-Al合金耐海水冲刷腐蚀性能的影响.结果表明,冲刷腐蚀96 h以前,腐蚀速率随着时间延长逐渐降低,96 h以后趋于稳定;海水流速对合金的腐蚀速率影响较大,5.0 m/s流速下合金腐蚀速率比1.5 m/s流速下高;相同冲刷时间和海水流速下,添加稀土后的合金腐蚀速率明显低于不添加稀土元素;1.5 m/s流速下冲刷168 h,稀土含量(质量分数)0.014 6%和0.035 2%的合金比不加稀土的合金腐蚀速率分别降低了2%和5%,在5.0 m/s流速下冲刷168 h后腐蚀速率分别降低了4%和43%;稀土添加后合金在腐蚀过程中表面钝化加快,合金的腐蚀速率降低较快,合金钝化膜质量更好.

Effect of RE on flushing corrosion resistance of Cu-Ni-Al alloy

Corrosion of the Cu-Ni-Al alloy in the artificial seawater was simulated on an erosion testing machine. Corrosion behavior of the Cu - Ni - Al alloy in different flushing time and different seawater flow velocity was analyzed. Effects of the rare earth element on corrosion resistance of Cu-Ni-Al alloy was emphasized. The results showed that corrosion rate decreases gradually with time before 96 h, and it tends to be stable after 96 h. The seawater flow velocity has a great effect on the corrosion rate. The corrosion rate at 5. 0 m/s is higher than that at 1. 5 m/s of the velocity. When the erosion time and the seawater flow velocity are same, the corrosion rare of the alloy with RE addition is significantly lower than that one without RE. When seawater flow velocity is 1. 5 m/s, flushing time is 168 h, corrosion rate of the alloys with rare earth of 0. 0146% and 0. 0352% decreases by 2% and 5% respectively, the corrosion rate of the alloy with RE addition decreases by 4% and 43% at 5. 0 m/s for 168 h. By adding rare earth, passivation of the alloy is accelerated during the corrosion process, corrosion rate of the alloy decreases rapidly and quality of the alloy passivation film is much better.