酸化缓蚀剂曼尼希碱缓蚀机理的电化学研究

Electrochemical Investigation on Corrosion Inhibition Mechanisms of Mannich Base in Hydrochloric Acid

由苯乙酮、甲醛及二乙胺合成了曼尼希碱,用电化学方法考察了该曼尼希碱在15%盐酸中对P110钢的缓蚀作用。20℃下的极化曲线表明P110钢在盐酸中发生阳极活性极化过程,随该曼尼希碱加入量的增大(0～1.0%),腐蚀速率减小,自腐蚀电位正移,表明该曼尼希碱为抑制阳极过程为主的缓蚀剂;EIS谱表明该曼尼希碱在钢表面形成的保护膜随温度升高(20～80℃)而减弱;随该曼尼希碱加入量增大而增强。用电化学方法测定的P110钢在15%盐酸中的腐蚀速率,在不加该曼尼希碱时随温度升高而急剧增大,20℃时为2.796g/m2.h,80℃时高达493.4g/m2.h,在同一温度下随曼尼希碱加量增大而减小,同一曼尼希碱加量下的缓蚀率随温度升高而增大,即该曼尼希碱的缓蚀效率随温度升高而增大。

A Mannich＇s base（MB） was synthesized from acetophenone,formaldehyde,and diethyl amine and its inhibitory capability for corrosion of steel P110 in 15% hydrochloric acid was studied by using electrochemical measurements. The polarization curves at 20℃ showed that steel P110 underwent activated anodic polarization processes of corrosion reaction in the acid and,when the dosage of MB increased from 0 to 1.0%,the corrosion rate lowered and the autocorrosion potential shifted toward positive direction,which indicated this MB controlling mainly the anodic processes of corrosion. The EIS spectra showed that the films formed by MB on steel surfaces weakened with increasing temperature from 20℃ to 80℃ and strengthened with increasing MB dosage up to 1.0%. The values of corrosion rate of steel P110 in the acid,determined by electrochemical measurements,increased dramatically with increasing temperature at the absence of MB,being of 2.796 g/m^2·h at 20℃ and 493.4 g/m^2·h at 80℃,and decreased with increasing MB dosage at a given temperature; the percentage corrosion inhibition at a given MB dosage increased with increasing temperature,or the inhibiting efficiency of this MB in the acid was higher at higher temperatures.