EQCM study of copper and iron corrosion inhibition in presence of organic inhibitors and biocides

Attention has been devoted to the application of quartz crystal microbalanc e (QCM) in the field of corrosion and corrosion inhibition. In-situ measure ments were performed on copper and iron surfaces. Copper corrosion inhibiti on by the application of several inhibitors was followed by QCM. Copper cor rosion inhibition in different electrolyte solutions such as acidic sodium sulphate and neutral sodium chloride were investigated. Different inhibitor compounds were tested for protection against copper corrosion. Three diffe rent groups of inhibitors were investigated; aromatic sulfoxides, benzo-hyd roxamic acid derivatives, and azole derivatives. Among the tested sulfoxide s, di-benzyl-sulfoxide (DBSO) produced the best protection, while p-chloro- benzo-fiydroxamic acid showed excellent protection among the benzo-hydroxam ic acid derivatives. Among the tested azole derivatives, 5-mercapto-1-pheny l-tetrazole (5-McPhTT) and 5-(4'-isopropylbenzylidene)-2,4-dioxotetrahydro- 1,3-thiazole (5-IPBDT) showed excellent inhibition properties against coppe r corrosion in acidic media. The effect of biocides, namely N-hydroxyalkyla ted amino acids, on biofilm formation has been investigated, too. From the attained results, it is clear that QCM is an essential tool for obtaining i mportant information on corrosion inhibition and its mechanism. (C) 2000 El sevier Science Ltd. All rights reserved.