Investigation of atmospheric corrosion of mild steel after treatment by several inhibitor solutions

Atmospheric corrosion is a common problem in the Gulf region in Saudi Arabia. Steel products produced locally have a problem of discoloration when stored in stockyards due to atmospheric corrosion. Corrosion inhibition of mild steel in the industrial and marine atmosphere of the Arabian Gulf region was investigated in this study. Sodium dihydrogen orthophosphate, dicyclohexylamine nitrite and sodium benzoate were used as inhibitors of the investigation. The three inhibitors were evaluated under atmospheric conditions by weight loss measurements and electrochemical techniques in a simulated solution of 2·0%NaCl and 1·0%Na₂SO₄. Sodium dihydrogen orthophosphate had the best performance among the three inhibitors. It was still effective at the end of 180 days of atmospheric exposure. The performances of dicyclohexylamine nitrite and sodium benzoate, on the other hand, were effective in the early stages of the atmospheric exposure (for ∼2 months). Their inhibition effectiveness deteriorated with further exposure to the atmosphere, being totally ineffective by the end of the exposure period.