Electrochemical and optical studies of two synthesized cobalt complexes as anti-corrosion agent for low-carbon steel in HCl medium

Abstract

Two novel synthesized Co(II) complexes, named diacetato(1-(2-methoxyphenyl)-N-(2-(phenylthio)phenyl)methanimine)cobalt(II) (CoMPM) and diacetato(2-(phenylthio)phenyl)-1-(2-(trifluoromethyl)phenyl)methanimine)cobalt(II) (CoPFM), have been investigated as an anti-corrosion agent for low-carbon steel in 1.0M HCl solution. The protection performance of Co(II) complexes was evaluated using electrochemical and optical methods. The inhibition efficiency was investigated as a function of exposure time, inhibitor concentration, and different potentiostatic potentials. CoPFM (99.4%) was found more efficient as a corrosion inhibitor in negative potentiostatic polarization conditions than CoMPM (98.4%). However, CoMPM (99.2%) showed a better protection when it was compared to CoPFM (95.7%) at the end of 120-h immersion.