用微分极化电阻测量技术研究有机添加剂对铝的缓蚀作用

STUDY ON THE CORROSION INHIBITION OF ORGANIC ADDITIVE FOR ALUMINUM USING DIFFERENTIAL POLARIZATION RESISTANCE TECHNIQUE

在30℃至50℃范围内,在1mol·1^(-1)MgCl_2电解液体系中,用微分极化电阻测量技术和微分电容测量技术研究十二烷基三甲基碘化铵(DTMAI)添加剂对铝的阳极过程的缓蚀作用。结果表明:DTMAI是铝的有效缓蚀剂,缓蚀效率随着浓度和温度的增加而增加;DTMAI吸附在铝表面上,且吸附服从Langmuir等温式。这种吸附的特点是吸附过程的总熵增加,且总熵变随温度升高而增加。温度对缓蚀效率的影响是由于熵效应而不是焓效应。因此,DTMAI在铝表面上的这种吸附作用是其具有良好缓蚀作用的基本原因。

The inhibition of dodecyltrimethylammonium iodide (DTMAI ) with various concentrations for the aluminum corrosion has been studied using the differential polarization resistance and the differential capacitance techniques in lmol·l-1 MgCl2 solution at 30-50℃. The results indicated that DTMAI is a perfect inhibitor for the aluminum corrosion in MgCl2 solution,and the inhibition efficiency of DTMAI is increased with raising temperature and concentration. The results also showed that the adsorption of DTMAI on the aluminum surface obeys Langmuir isotherm. The entropy change of overall adsorption process is positive,and it increases with raising temperature. The effect of temperature on the inhibition efficiency is attributed to the entropy change rather than the enthalpy effect. Consequently,the adsorption of DTMAI on the aluminum surface is predicted to be the main effect of the corrosion inhibition.