5083鋁合金在含硫離子的氯化鈉水溶液中之電化學阻抗頻譜研究

EIS study of 5083 Aluminum Alloy in Sulfide Containing 3.5% NaCl Solution

5083鋁合金在3.5% NaCl水溶液中的電化學阻抗頻譜量測結果顯示，其腐蝕反應為活化控制機構。當溶液中添加1 ppm硫離子時，由電荷轉移阻抗變化值得知，其腐蝕速率降為約原來的三分之一；但當硫離子濃度介於10～1000 ppm時，其腐蝕速率隨硫離子濃度升高而增大。另一方面，在含100ppm硫離子的溶液中，且電位控制在低於鈍態膜崩破電位時，腐蝕反應受擴散控制；而在鈍態膜崩破電位或是電位高於該值時，電荷轉移電阻急遽降低，且出現感抗效應。

EIS study of 5083 aluminum alloy in sulfide containing 3.5% NaCl solution showed that the corrosion reaction was under activation control. The corrosion rate was reduced to one third when 1 ppm of sulfide was added. However, the corrosion rate increased as increasing of sulfide concentration when its amount between 10 ppm and 1000 ppm. On the other hand, in the 3.5%NaCl solution containing 100 ppm of sulfide, the corrosion reaction was under diffusion control when the electrode potentials were more active than the breakdown potential (Eb). At Eb or potentials more noble than Eb, the charge transfer resistance decreased rapidly and inductive resistance appeared.