Realization of Synergism in Sodium Tungstate-Zn2+-N-(Phosphenomethyl) Iminodiaceticacid System in Well Water

Abstract

The aim of this present work is to study, the corrosion behavior of carbon steel in well water in the presence of sodium tungstate (ST)-Zn 2+ -N-(phosphenomethyl) iminodiaceticacid (NPMIDA) solutions. Electrochemical studies and FTIR spectral studies and weight loss study have been employed. It was found that the inhibition efficiency (IE) of ST (50 ppm)-Zn 2+ (10 ppm) was improved from 8% to 82% by the addition of 150 ppm of NPMIDA. The protective film consists of Fe 2+ -WO4 2, Fe 2+ -NPMIDA complex on anodic site and Zn(OH)2 complex at cathodic site. The NPMIDA-ST-Zn 2+ system increases linear polarization resistance value, decreases corrosion current, increases charge transfer resistance and decreases double layer capacitance value. Based on the above results a mechanism of corrosion inhibition is proposed.