(北京科技大學(xué) 腐蝕與防護(hù)中心，北京 100083)
摘 要: 通過鹽霧腐蝕試驗(yàn)?zāi)M研究7A04鋁合金在海洋大氣環(huán)境中的腐蝕初期規(guī)律，采用電化學(xué)交流阻抗測(cè)試和掃描Kelvin探針技術(shù)，研究7A04鋁合金在初期腐蝕過程中的電化學(xué)行為。結(jié)果表明：Cl−對(duì)鋁合金腐蝕有顯著的加速作用，鹽霧試驗(yàn)初期表面出現(xiàn)點(diǎn)蝕坑；隨鹽霧時(shí)間增長，點(diǎn)蝕相互連接并擴(kuò)展，電化學(xué)反應(yīng)阻抗下降。掃描開爾文探針測(cè)試結(jié)果表明：隨腐蝕的不斷進(jìn)行，金屬表面陰極區(qū)和陽極區(qū)不斷發(fā)生變化，呈現(xiàn)局部腐蝕的特征，表面電位也隨時(shí)間逐漸升高，陰極區(qū)和陽極區(qū)逐漸變得明顯，腐蝕反應(yīng)處于不斷加速過程。
關(guān)鍵字: 7A04鋁合金；大氣腐蝕；電化學(xué)交流阻抗；掃描Kelvin探針
7A04 aluminium alloy in marine atmosphere
（Corrosion and Protection Center, University of Science and Technology Beijing, Beijing 100083, China）
Abstract: The initial corrosion of 7A04 aluminium alloy in marine atmosphere was studied. Salt fog test was used to simulate the marine atmospheric environment. Electrochemical impedance spectroscopy (EIS) and scanning Kelvin probe (SKP) were employed to investigate the electrochemical behavior of 7A04 aluminium alloy in marine atmosphere. The results show that the Cl− can accelerate the atmospheric corrosion of 7A04 aluminium alloy during the beginning exposure period. Pittings appear in the initial stage of salt fog test and link each other to expand with prolonging test time. The electrochemical impedance magnitude declines during the corrosion test. The SKP results indicate that the anodic and cathodic areas change constantly with distinct character of localized corrosion. When the corrosion process continues, the surface potential of 7A04 aluminium alloy increases, while anodic and cathodic area distinguish evidently from each other. Atmospheric corrosion of 7A04 aluminium alloy is promoted during the initial stage in marine air.
Key words: 7A04 aluminium alloy; atmospheric corrosion; EIS; SKP
