Naslov
Impedance Investigation of Corrosion Inhibition of Armco Iron by Thiourea

Autori
Metikoš-Huković, Mirjana ; Babić, Ranko ; Grubač, Zoran ; Brinić, Slobodan

Izvornik
Journal of applied electrochemistry (0021-891X) 26 (1996), 4; 443-449

Vrsta, podvrsta i kategorija rada
Radovi u časopisima, članak, znanstveni

Ključne riječi
impedance spectroscopy; adsorption; corrosion inhibition; iron; thiourea

Sažetak
The inhibitive action of thiourea on the corrosive behavior of ARMCO iron was investigated in deaerated 0.5 M H_2S0_4 solution, by means of electrochemical impedance spectroscopy. The inhibitor effectiveness increases with concentration, reaches a maximum (at about 1 mm) and then decreases. The adsorptive behavior of thiourea on the electrode surface up to its peak follows a Frumkin type isotherm with lateral repulsion, where the molecules are vertically adsorbed on the iron surface via the sulfur atom. Thiourea acts as a mixed inhibitor up to the critical concentration. It decreases the dissolution of iron and the hydrogen evolution reaction by blocking the electrode surface. The free energy of adsorption DELTA G_ad = -39 kJ mol^(-1) and the attraction constant a = -4.4.

Izvorni jezik
Engleski

Znanstvena područja
Kemija

POVEZANOST RADA