The corrosion behavior of 5083 aluminum magnesium alloy in NaCl solution at different concentra-tions was studied by polarization curve method and AC impedance spectroscopy in scanning electrochemical microscopy (SECM). The results show that the corrosion of alloy is neutralized in neutral NaCl solution. With the increase of salinity, the damage of Cl-to the alloy matrix is aggravated. The corrosion potential is positive and the pitting potential is decreased. The electrochemical impedance spectroscopy is only 1 capacitive arc, showing a contraction trend. At the same time, the impedance decreases, the phase angle increases, the dis-persion index decreases, and the corrosion resistance of the alloy decreases. The strong activation of Cl-in the solution,will damage the alloy surface oxide film,gradually replacing the OH-in corrosion products of Al(OH)3 and formation of new corrosion products of AlCl3.%采用扫描电化学显微镜(SECM)中的极化曲线法和交流阻抗图谱法研究5083铝镁合金在不同浓度NaCl溶液中的腐蚀行为,结果表明:合金在中性NaCl溶液中的腐蚀为钝化材料体系,随着盐度的增加,Cl-对合金基体的破坏加剧,腐蚀电位正移,点蚀电位减小,其电化学阻抗谱中仅有1个容抗弧且呈现收缩趋势.同时,阻抗减小,相位角增加,弥散指数降低,合金的耐腐蚀性能下降.溶液中存在强活化作用的Cl-,会损坏合金表面的氧化膜,逐渐取代腐蚀产物Al(OH)3中的OH-,生成新的腐蚀产物AlCl3.
展开▼
