Considerations Based on the HSAB Principle on Inhibition Mechanisms of Precipitation Inhibitors in Aqueous Acid Solutions

Abstract

Inhibition mechanisms of many corrosion inhibitors in deaerated acid and oxygenated neutral solutions have been discussed on the basis of the hard and soft acids and bases principle （HSAB principle）. However, inhibition effects of precipitation inhibitors such as propargyl alcohol CH≡CCH₂OH, bismuth （III） ion, Bi^3＋ and benzylthiocyanate, C₆H₅CH₂SCN, which are effective for corrosion of metals in the acid solutions have not been described. In this paper, the inhibition mechanisms of these precipitation inhibitors in aqueous acid solutions are discussed based on the HSAB principle.