7A04-T6铝合金中性盐雾腐蚀初期性能

Corrosion Behavior of 7A04-T6 Aluminum Alloy at a Early Stage of Neutral Salt Spray Testing

7A04-T6铝合金被广泛应用于航空领域，目前对其大气腐蚀初期行为的报道较少。对7A04-T6铝舍金进行了4～48h的连续中性盐雾腐蚀，采用失重法和动电位极化曲线法对其初期腐蚀规律和行为进行了研究，利用扫描电镜（SEN）对腐蚀初期的表面形貌进行了观察，并对不同腐蚀时间的试样进行了拉伸。结果表明：7A04-T6铝合金盐雾腐蚀初期，从点蚀开始，随着腐蚀时间的延长逐渐发展为剥蚀；腐蚀动力学遵循指数增长规律；盐雾腐蚀后抗拉强度降低，腐蚀时间越长，抗拉强度下降越明显。

7A04-T6 aluminum alloy was allowed to undergo4,8,12,24,48 h of neutral salt spray testing,and its corrosion behavior at the early stage of corrosion was studied by weight loss method and potentiodynamic polarization test,The morphology of the corroded surface was observed with a scanning electron microscope,and the tensile strength of Al alloy after different duration of neutral salt- spray testing was measured.Results showed that the corrosion of 7A04-T6 Al alloy began with pitting and expanded to exfoliation corrosion rapidly with prolonging test time,and the corrosion kinetics of 7A04-T6 Al alloy obeyed the exponential growth rule.Moreover,the tensile strength of 7A04-T6 Al alloy tended to decrease greatly after corrosion in neutral salt atmosphere,and it was reduced more prominently as the corrosion time was extended.