Mercapto-imidazole compounds are particularly worth investigating as they are potential Cu corrosion inhibitors. One of them is 2-mercaptobenzimidazole (MBIH) [10–20], for which some corrosion studies already exist wherein the research was mainly focused on the polymerized MBIH surface layer (see below). However, scientific interest in the MBIH compound and consequently detailed examination of its action is still far less than for BTAH [2]. MBIH
action remains relatively unexamined, even though this compound is a very effective Cu corrosion inhibitor in chloride media, as will be shown in this work. This study presents new insights into the MBIH corrosion inhibition ability, corrosion processes (especially by including diffusion analysis), and the manner of inhibitor action. In order to make a comprehensive investigation, the surface chemistry of MBIH adsorbed on Cu from 3 wt.% NaCl solution using
X-ray photoelectron spectroscopy will be studied in Part II [21] to gain further insight into the molecular binding and models of adsorption. The acronyms BTAH or BTA and MBIH or MBI are used to emphasize the N–H hydrogen removal from BTAH or MBIH molecules.This is especially needed for the designation of complexes with Cu(I) (e.g. Cu(I)–MBIH or Cu(I)–MBI) [2].