盐酸溶液中碘化钾对金属的缓蚀效应

Inhibition Effect of Potassium Iodide on Metal in Hydrochloric Acid Solution

通过对 30 4、31 6和 2 0钢的电化学测量和腐蚀失重试验 ,研究了碘化钾的缓蚀效应。试验结果表明 ,在 HCl溶液中加入碘化钾有明显的缓蚀效果 ,温度影响金属的缓蚀效应 ,温度增加缓蚀效果明显。极化曲线表明加入碘化钾使腐蚀电流大大降低 ,阴极电位有较大增加 。

The inhibition effect of potassium iodide in hydrochloric acid solution had been examined using weight loss and electrochemical measurements. Potassium iodide was found to be an excellent inhibitor for 20, 304, 316 steels. Adding 0 1 mol KI to hydrochloric acid solution, the inhibitor efficiency for 20, 304 and 316 steels are 81%, 64% and 58% respectively. Inhibitor effect on 20 steel is most remarkable. The inhibitor effect will increase when KI content increases. The presence of potassium iodide lowers both activation energy and rate of reaction. The result shows that potassium iodide acts as an anodic inhibitor particularly at higher concentrations and as a cathodic inhibitor at lower concentrations. Influence of temperature on the inhibition effect was also investigated, the inhibition effect increases as temperature increases. Polarization measurements indicated that potassium iodide makes the corrosion current decrease and corrosion potential shift towards the positive direction.