Corrosion inhibition by phenyl phosphonate and Zn²⁺

Abstract

A formulation consisting of 300ppm sodium salt of phenyl phosphonic acid (PPA) and 50ppm Zn²⁺ is 95 per cent efficient in inhibiting the corrosion of mild steel in a neutral aqueous environment containing 60ppm chloride. A higher concentration of Zn²⁺ lowered inhibition efficiency. This is due to the formation of an insoluble Zn²⁺‐PPA complex in the solution. It is found that, in solution, both the phosphonate group and the phenyl group of PPA are involved in the formation of the complex with both Zn²⁺ and Fe²⁺, whereas in the solid state, only the phosphonate group is involved.

Citation

Rajendran, S., Apparao, B.V. and Palaniswamy, N. (1998), "Corrosion inhibition by phenyl phosphonate and Zn²⁺", Anti-Corrosion Methods and Materials, Vol. 45 No. 3, pp. 158-161. https://doi.org/10.1108/00035599810216830