航空用鋁合金在酸性鹽霧環(huán)境中腐蝕電化學(xué)

航空用鋁合金在酸性鹽霧環(huán)境中腐蝕電化學(xué)Corrosion Electrochemistry of Aluminum Alloy for Aviation in Acid Salt Spray Environment

用失重法和電化學(xué)方法研究2A12，5A06和7A04鋁合金在中性和酸性（pH≈5）連續(xù)鹽霧環(huán)境下的腐蝕過程。通過金相顯微鏡和接觸角表面分析儀觀察其金屬相界面處的腐蝕形貌和表面狀態(tài)，分析腐蝕機理。結(jié)果表明：失重法、極化曲線Tafel外推法和電化學(xué)阻抗譜法均顯示3種鋁合金在中性鹽霧中腐蝕速率的大小關(guān)系為7A04>2A12>5A06；在酸性鹽霧中腐蝕速率的大小關(guān)系為7A04> 5A06>2A12；鋁合金表面與中性和酸性鹽溶液的接觸角分別為70.9°和52.6°，酸性鹽溶液的接觸角小于中性鹽溶液的接觸角，可能是因為氫離子增多使陰極反應(yīng)右移，加速陽極溶解，破壞了鋁合金表面的氧化膜。

The corrosion processes of 2A12, 5A06 and 7A04 aluminium alloy in neutral and acid (pH≈5) continuous salt spray environment were studied with weight loss method and electrochemical method. The morphology and surface condition in the interface of metal phase was studied by metallographic microscope and contact angle surface analyzer, and the corrosion mechanism was analyzed. Weight loss method, polarization curves by Tafel extrapolation and electrochemical impedance spectroscopy show that the 3 kinds of aluminum alloy have the relationship of corrosion rate 7A04>2A12>5A06 in neutral salt spray as well as 7A04> 5A06>2A12 in acidic salt spray. The contact angles of the aluminum alloys surface with neutral and acidic salt solution conditions are 70.9?nd 52.6°respectively. The reason why the contact angle with acid salt solution is smaller than that with neutral salt solution is probably that the increase of the hydrogen ions may cause the cathodic reaction to move to the right, accelerate anodic dissolution and destroy the oxide film on the surface of the aluminum alloy.

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