The Effect of Organic Compounds on the Corrosion of Zinc in Aqueous Soultions

Abstract

The effect of benzotriazole (BTA), tolytriazole (TTA), benzo (c) cinnoline (E1), benzo (c) cinnoline 5-oxy (E2), 2,2-dinitro benzidyn (E4) and 2-Aminobenzo (c) cinnoline (E5), were investigated on the corrosion of pure zinc metal in four different aqueous solutions. The corrosion rates of the species were determined by electrochemical current density-potential curves. Primary studies have shown that BTA and TTA have inhibitory effect on copper, and compounds containing nitrogen and sulphur reduce the corrosion rate of zinc. The inhibition efficiencies were studied at different pH values in order to clarify the effect of organic compounds. The results revealed that BTA and TTA act as effective inhibitors on zinc in HCl, NaOH and NaCl solutions. Cinnolines were only effective in NaOH solution.

Dependence of Inhibition Effects of Oxalate, Tungstate, Molybdate and Phosphate on Purity of Zinc Metal

“…In recent studies, the inhibition effect of inorganic onions such as C2O4 -2 , MoO4 -2 , WO4 -2 and HPO4 -2 have been investigated on the corrosion of zinc, zinc alloys and some other metals [10][11][12][13][14][15]19]. Oxalate ions were found to be an effective inhibitor in our previous studies on magnesium, zinc, copper and brass especially in NaCl solutions [16][17][18][19]. This effect decreases with increasing concentration of C2O4 -2 and the most effective concentration was observed to be 10 -3 M [17].…”

Molecular-Level Understanding of the Inhibition Efficiency of Some Inhibitors of Zinc Corrosion by Quantum Chemical Approach

“…To improve its corrosion resistance, surface pretreatments, coatings, and additives are applied to the corrosive media. Numerous compounds of varied chemical nature have been tested as potential corrosion inhibitors of zinc in acidic media; , among them, methylthio phenyl moiety-containing compounds are particularly interesting. They constitute a group of compounds employed in pharmaceutical products …”

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[2][3][4] phenyl] acetohydrazide (HYD) and 5-[4-(methylthio)benzyl]-4H-1,2,4-triazole-3-thiol (TRD) are compounds that contain methylthiophenyl moiety and substantially inhibit corrosion of zinc in acidic medium. The relationship between molecular structures and inhibition efficiencies of these intriguing inhibitors remains the subject of intense speculation, as introduction of thiophenyl group in strategic positions of many molecules alters their activity.

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