H_2SO_4介质中KI在冷轧钢表面的吸附及缓蚀作用

Adsorption and Inhibition Effect of KI on Cold Rolled Steel Surface in H_2SO_4 Solution

用失重法和电化学法研究了在1．0～6．0mol／L H2SO4介质中，20—60℃时Ⅺ在冷轧钢表面上的吸附及缓蚀作用。结果表明，KI在H2SO4中具有非常好的缓蚀作用，为混合抑制型缓蚀剂，最大缓蚀率超过98％；KI在钢表面的吸附符合Langmuir吸附模型。通过吸附热力学和动力学公式分别求出了相应的吸附热力学参数（吸附自由能△G^0，吸附热△H^0，吸附熵△S^0）和动力学参数（腐蚀速度常数k．腐蚀动力学参数B），并根据这些参数详细讨论了缓蚀作用机理。

The adsorption and inhibition effect of KI on cold rolled steel （CRS） surface in 1.0-6.0 mol/L H2SO4 solution at 20 oC-60 oC has been investigated by weight -loss and petentiedynamic polarization methods. The results show that KI is a good inhibitor for CRS in H2SO4 solution, and the maximum inhibition efficiency is higher than 98%. The adsorption of KI on CRS surface obeys Langmuir adsorption isotherm equation. Polarization curves show that KI acts as a mixed - type inhibitor in H2SO4. The experimental data have been treated with adsorption theory and thermodynamic equation. Three adsorption thermodynamic parameters （ adsorption free energy △GO, adsorption heat △H0, adsorption entropy △S0） and two kinetic parameters （corrosion rate constant k, kinetic reaction constant B） are also calculated. The inhibitive mechanism is discussed in detail according to these parameters.