The inhibition of mild steel corrosion in 1 M HCl in the presence of linear and cyclic thiocarbamides - Effect of concentration and temperature of the corrosion medium on their protective action

The inhibiting action of linear and cyclic thiocarbamides on mild steel corrosion in 1 M HCl is examined. It is found that their inhibiting effect grows with the increase of the temperature of the corrosion medium. Their presence in the solution decreases the apparent activation energy of the hydrogen evolution reaction. Inhibitor chemisorption on the metal surface is described by the Temkin adsorption isotherm. The thiocarbamides studied are adsorbed through the S-atom which is the adsorption centre, forming a donor-acceptor bond between the unpaired electrons of the S-atom and the positive active centres of the metal surface. (C) 1997 Elsevier Science Ltd.