电偶对中6A01铝合金的电化学腐蚀行为研究

为了解决高速列车环境下6A01铝合金的电偶腐蚀问题,利用电化学阻抗谱和极化曲线等电化学方法研究了6A01铝合金在不同溶液中的电偶腐蚀行为。结果表明:6A01铝合金在NaCl溶液和模拟污水溶液中以点蚀为主,模拟污水溶液中铝合金的腐蚀速率较小,腐蚀速率随时间先增大后减小,再增大再减小,最后趋于稳定,铝合金的耐蚀性能减弱。铝合金的腐蚀速率的变化与试样表面钝化膜、点蚀坑的大小、腐蚀产物的积累及腐蚀溶液有关。在铝合金使用过程中,应避免与异种金属的接触,考虑电偶效应及不同环境的适用性。

Study on the Electrochemical Corrosion Behavior of 6A01 Aluminum Alloy in Galvanic Pair

In order to solve the problem of galvanic corrosion of 6 A01 aluminum alloy in high-speed train environment, the galvanic corrosion behavior of 6 A01 aluminum alloy in different solutions was studied by electrochemical methods such as electrochemical impedance spectroscopy and polarization curve. Results showed that the 6 A01 aluminum alloy was mainly pit-corroded in NaCl solution and simulated sewage solution, while the corrosion rate of aluminum alloy in simulated sewage solution was relatively small. The corrosion rate first increased and then decreased with time, then increased and then decreased, and finally tended to be stable, and the corrosion resistance of aluminum alloys weakened. In addition, the change of the corrosion rate of aluminum alloy was related to the passive film on the surface of the sample, the size of the pitting pit, the accumulation of corrosion products and the corrosion solution. Considering that the galvanic effect and different environmental suitability, the aluminum alloy should be avoided to contact with dissimilar metals during the use process.