6082-T6铝合金在模拟沿海大气环境下的腐蚀行为和腐蚀机理

Corrosion Behavior of Al-alloy 6082-T6 in Simulated Marine Atmospheric Environment

通过盐雾实验模拟沿海大气环境,研究了6082-T6铝合金的腐蚀行为及机理。结果表明:6082-T6铝合金的腐蚀失重与腐蚀时间的关系可用幂指数函数表示:D=0.44t0.45;腐蚀实验初期,Cl-促使铝合金发生点蚀,随后点蚀产物逐渐汇聚堆叠,进入全面腐蚀阶段;随着腐蚀时间延长,腐蚀产物层的孔隙减少且厚度不断增加;当腐蚀实验时间在20~30 d之间,外层腐蚀产物的侵蚀溶解占主导地位,使其厚度减小且变为疏松的棱状堆叠;进一步延长腐蚀时间,表面的腐蚀产物转变为致密堆叠的层片状。电化学测试分析表明,随着腐蚀时间的延长,6082-T6铝合金腐蚀电流密度Icorr呈现先增大,后减小,再增大,最后下降的趋势;容抗弧半径呈现先降低,后升高,再下降,最后回升的趋势。

The corrosion behavior of Al-alloy 6082-T6 in a simulated marine atmospheric environment was investigated by salt spray tester. Results showed that the relationship between the corrosion mass loss and corrosion time followed the power exponential equation： D=0.44t0.45. At the initial corrosion stage, pitting corrosion occurred by the action of Cl-, then corrosion product gathered and stacked gradually and as a result, the pitting corrosion turned to be general corrosion. With corrosion time going by, the corrosion product layer became thick and compact. When corrosion time was between 20~30 d, the outer corrosion product layer was thin and loose because the dissolution played the dominant role. With the increasing corrosion time, the outer corrosion products became compact stacks of flakes, while Icorrunderwent increasing firstly, decreasing next, then increasing and finally decreasing again. In the meantime, capacitive reactance arc experienced shrunking firstly, expanding next, then shrunking and finally expanding again.