(1. 蘭州理工大學(xué) 材料科學(xué)與工程學(xué)院，蘭州 730050；2. 河南科技大學(xué) 材料科學(xué)與工程學(xué)院，洛陽 471003)
摘 要: 通過測定Al-Zn-Sn-Ga陽極在3.5% NaCl(質(zhì)量分數(shù))溶液中浸泡不同時間的電化學(xué)阻抗譜(EIS)，研究該陽極的腐蝕發(fā)展過程和腐蝕特征。結(jié)果顯示：當(dāng)合金剛被浸入3.5% NaCl溶液時，EIS譜為反應(yīng)電阻很大的容抗弧，表明此時合金處于鈍化態(tài)；隨著浸泡時間的延長，EIS譜中高頻段的容抗弧明顯減小且低頻段出現(xiàn)感抗弧，合金進入點蝕期；繼續(xù)延長浸泡時間，EIS譜中除高頻段的容抗弧和中、低頻段感抗弧外，在低頻段出現(xiàn)另一容抗弧，合金處于點蝕擴展期；隨著浸泡時間的繼續(xù)增加，低頻段感抗弧消失，EIS譜由兩個容抗弧組成，合金達到均勻腐蝕期。因此，合金的腐蝕由鈍化態(tài)開始，經(jīng)點蝕期和點蝕擴展期，達到均勻腐蝕期。
關(guān)鍵字: 鋁合金；犧牲陽極；電化學(xué)阻抗譜；腐蝕行為
Al-Zn-Sn-Ga anode during corrosion process
（1. School of Materials Science and Engineering, Lanzhou University of Technology, Lanzhou 730050, China;
2. School of Materials Science and Engineering, Henan University of Science and Technology, Luoyang 471003, China）
Abstract:The corrosion extension process and characteristics of Al-Zn-Sn-Ga anode in 3.5% NaCl (mass fraction) solution for different immersion times were investigated by electrochemical impedance spectroscopy (EIS). The results show that the EIS spectrum at the beginning of immersion consists of a large capacitive arc, indicating the passivation. With the increase of immersion time, the capacitive arc at high frequency is significantly reduced, and an inductive loop at low frequency appears, implying the pitting. With extending the immersion time, another capacitive arc at low frequency appears in EIS spectra, suggesting the pitting growth. With the further prolonging of immersion time, the inductive arc at low frequency disappears, and the EIS spectrum is composed of two capacitive arcs, hinting the uniform corrosion. So, the corrosion of Al-Zn-Sn-Ga alloy initiates from the passive film, and then the pitting, followed by the pitting growth, and finally the uniform corrosion.
Key words: aluminum alloy; sacrificial anode; electrochemical impedance spectroscopy; corrosion behavior
