Effect of some anions on the anodic dissolution of Delta-52 steel in sulphuric acid solutions

The anodic dissolution of hot-rolled Delta-52 steel (an Egyptian product) was studied potentiodynamically in H₂SO₄ solutions of various concentrations. The rate of dissolution increases with increasing acid concentration. The effects of the addition of Cl^-, Br^- and I^- anions on the dissolution kinetics of the electrode in 0.1 M H₂SO₄ were investigated. The data reveal that the Cl^- ion participates in the anodic dissolution while both the Br^- and I^- ions decrease the steel dissolution reaction.

The addition of NO₂^-, CrO₄^3- anions to the H₂SO₄ solution inhibits the anodic reaction of steel dissolution. The dissolution current density j in the Tafel region varied with the concentration C_inh of the added anions according to the relation. log j=a−blogC_inh where a and b are constants.