Corrosion of inhibitor treated carbon steel during wet/dry cycling tests

Abstract

Purpose

The purpose of this paper is to study the inhibition of carbon steel corrosion under wet/dry conditions using electrochemical techniques.

Design/methodology/approach

Sodium dihydrogen orthophosphate, dicyclohexylamine nitrite and sodium benzoate were used as inhibitors in the investigation. Plain carbon steel specimens were treated with three different inhibitors for a set period of time. One group of the specimens was subjected to 60 wet/dry cycles whilst a second group was kept continuously immersed in distilled water during the same period. The corrosion rates of the specimens were determined by electrochemical methods at several intervals during corrosion.

Findings

The three inhibitors showed good performance during the whole 60 days of wet/dry cycling. Sodium dihydrogen orthophosphate was the best of the three, giving the lowest corrosion rates. However, during full immersion tests in distilled water, specimens that had been treated with dicyclohexylamine nitrite and sodium benzoate performed better than did those treated with sodium dihydrogen orthophosphate. Moreover, the corrosion rates were significantly higher in the case of wet/dry cycling due to differential aeration created through partial immersion, which was a consequence of the wet and dry cycling process.

Originality/value

This study showed the beneficial effect of inhibitors in slowing down the corrosion of steel. Furthermore, wet/dry cycling of steel samples in the laboratory produced corrosion rates that were comparable to those measured under actual outdoor conditions.

Citation

Saricimen, H. (2009), "Corrosion of inhibitor treated carbon steel during wet/dry cycling tests", Anti-Corrosion Methods and Materials, Vol. 56 No. 3, pp. 162-167. https://doi.org/10.1108/00035590910955522