Solvents role on hcl-induced corrosion of mild-steel - its control by propargyl alcohol and metal-cations

Abstract

The inhibitive effects of propargyl alcohol (PA) with some metal cations, namely Cu2+, Cr6+, Ni2+, and As3+, have been studied for mild steel corroding in 0.1 M hydrochloric acid solutions of methanol and water at 25 +/- 1-degrees-C. Weight loss and electrochemical techniques have been used to investigate these effects. PA and PA with metal cations have been found to afford less protection in acidified methanol than in the water-HCl solution. In both cases, the addition of PA moves the steady-state corrosion potential of the system in a more noble direction than in blank solutions. The shift is greater for the water-HCl solution than the acid methanol system. Addition of the above metal cations with PA to the electrolyte invariably improve the protective property of PA in methanol-HCl solutions. For water-acid solution, the metal ions are detrimental (except As3+). Possible explanations for this behavior are described.