Mu Guannan, Li Xianghong
Department of Chemistry, Yunnan University, People's Republic of China.
J Colloid Interface Sci. 2005 Sep 1;289(1):184-92. doi: 10.1016/j.jcis.2005.03.061.
The inhibiting action of a nonionic surfactant of Tween-20 on the corrosion of cold rolled steel (CRS) in 0.5-7.0 M sulfuric acid (H(2)SO(4)) was studied by weight loss and potentiodynamic polarization methods. Atomic force microscope (AFM) provided the surface conditions. The results show that inhibition efficiency increases with the inhibitor concentration, while it decreases with the sulfuric acid concentration. The adsorption of inhibitor on the cold rolled steel surface obeys the Langmuir adsorption isotherm equation. Effect of immersion time was studied and discussed. The effect of temperature on the corrosion behavior of cold rolled steel was also studied at four temperatures ranging from 30 to 60 degrees C, the thermodynamic parameters such as adsorption heat, adsorption free energy, and adsorption entropy were calculated. The results revealed that the adsorption was physisorption mechanism. A kinetic study of cold rolled steel in uninhibited and inhibited acid was also discussed. The kinetic parameters such as apparent activation energy, pre-exponential factor, rate constant, and reaction constant were calculated for the reactions of corrosion. The inhibition effect is satisfactorily explained by both thermodynamic and kinetic models. Polarization curves show that Tween-20 is a cathodic-type inhibitor in sulfuric acid. The results obtained from weight loss and potentiodynamic polarization are in good agreement, and the Tween-20 inhibition action could also be evidenced by surface AFM images.
采用失重法和动电位极化法研究了吐温-20非离子表面活性剂在0.5 - 7.0 M硫酸（H₂SO₄）中对冷轧钢（CRS）腐蚀的抑制作用。原子力显微镜（AFM）提供了表面状况。结果表明，缓蚀效率随缓蚀剂浓度的增加而提高，随硫酸浓度的增加而降低。缓蚀剂在冷轧钢表面的吸附服从朗缪尔吸附等温式。研究并讨论了浸泡时间的影响。还在30至60℃的四个温度下研究了温度对冷轧钢腐蚀行为的影响，计算了吸附热、吸附自由能和吸附熵等热力学参数。结果表明吸附为物理吸附机理。还讨论了冷轧钢在未加缓蚀剂和加缓蚀剂酸中的动力学研究。计算了腐蚀反应的表观活化能、指前因子、速率常数和反应常数等动力学参数。热力学和动力学模型都能令人满意地解释缓蚀效果。极化曲线表明吐温-20在硫酸中是一种阴极型缓蚀剂。失重法和动电位极化法得到的结果吻合良好，吐温-20的缓蚀作用也可由表面AFM图像得到证实。
