Tin corrosion inhibition by molybdate ions in 0.2 M maleic acid solution: Electrochemical and surface analytical study

Abstract

<p>The inhibition efficiency of molybdate ions (MoO<sub>4</sub><sup>2-</sup>) against tin corrosion in 0.2 M Malic acid has been studied using electrochemical (DC and AC) and surface analytical methods (SEM and EDX). The electrochemical polarization curves revealed the presence of an active/passive transition of the tin electrode. The electrochemical impedance measurements (EIS) confirmed the benefic effect of increasing MoO<sub>4</sub><sup>2-</sup> concentration on the inhibition efficiency (η %) (reaching η<sub>max </sub>≈ 88% at 0.02 M), whereas η % decreases by increasing temperature. The molybdate ions inhibition mechanism was attributed to the adsorption on the metal surface involving the formation of the adsorbed protective layer.<strong></strong></p>

Assessment of Corrosion Inhibition Performance and Adsorption Thermodynamics of Hydrogen Phosphate (HPO42−) and Molybdate (MoO42−) Oxyanions on Tin in Maleic Acid

“…Some investigations demonstrated similar behavior by investigating the mild steel corrosion inhibition by HPO 4 2− ions in NaCl solution of [10]. In an earlier contribution, it was shown that in a contradictory tendency, the addition of MoO 4 2− ions to a synthetic medium stimulates the dissolution of tinplate regardless of raising the temperature [18].…”

“…Several investigations reported the low toxicity and eco‐friendly suitability of molybdate anions (MoO 4 2− ), as tin corrosion inhibitors in different media [16, 17]. In a previously published contribution, we demonstrated that molybdate anions hinder the pitting corrosion of tinplate in a synthetic media analogous to industrial water comprising chloride, sulfate, and hydrogen carbonate ions; the pitting phenomenon decelerated and simultaneously accelerate the uniform corrosion by involving the untinned process [18].…”