LC4铝合金在模拟污染大气环境中的腐蚀行为

通过干湿周浸循环加速腐蚀试验,用NaHSO3和NaCl分别模拟对大气腐蚀有明显影响的两种大气污染组分SO2和Cl-.利用失重分析、表面形貌观察和腐蚀产物分析,研究了LC4铝合金在模拟污染大气环境中的腐蚀行为和机理.研究发现,在0.02 mol/L NaHSO3和0.02 mol/L NaHSO3＋0.006 mol/L NaCl两种加速腐蚀介质中,不论包铝层存在与否,LC4腐蚀失重均与腐蚀时间有线性关系;Cl-在HSO3-存在的情况能够更有效产生点蚀源,破坏LC4表面的氧化膜,加速LC4腐蚀;试样放置的角度对LC4腐蚀有较大的影响.

CORROSION BEHAVIOR OF Al ALLOY LC4 IN SIMULATED POLLUTED ATMOSPHERIC ENVIRONMENT

The corrosion behavior of typical high-strength aluminum alloy LC4 was studied by accelerated corrosion tests of cyclic wet-dry intermittent immersion designed to simulated industrially polluted atmospheric environment,and corrosion mechanism was also discussed.The main experimental techniques include mass loss,morphological check of samples and analysis of corrosion products in different test time.The result shows that LC4,with or without cladding,has linear relationship between mass loss and test time in two chemical media,0.02 mol/L NaHSO_3 and 0.02 mol/L NaHSO_3+0.006 mol/L NaCl respectively.Angle of setting samples was another important factor that can cause corrosion of aluminum alloys.Angle of setting exerts its effect by varying the wetness time of the surface of samples,longer wetness time with less angle of setting and vice versa.A layer of cladding on high-strength aluminum alloys can raise resistance of atmospheric corrosion evidently.