Effects of thiourea on the corrosion of low carbon steel in hydrochloric acid solution

Abstract EN

The corrosion rate ؛٠' low carbon steel 4 ١٦؛M hydrochloric acid with and without presence of thiourea has been studied by gra^metric and ga$ometric methods over the temperature range 303-333 K.

The percentage protection of Steel increases with the decrease of thiourea concentration at various temperature range 303-333 K and approaching ةةآاج؛آا، protection (86.82%) at 303K by using lxl()~4 M of thiourea.

The high concentration of thiourea (1^أ“ها M), enhances the corrosion rates and act as depolariser for the hydrogen evolution reaction, with H2S being a product of the chemical depolarisation stage.

The H2S is considered to be adsorbed ٨؛ the s~2, HS” state, forming activated sites where anodic dissolution is thereby enhanced.

The results were discusscd on basis of adsorption of dissociated thiourea molecules on Steel surface.

The energies of activation have been calculated for the corrosion process 0؛' the carbon Steel in acid from corrosion rates in the absence and the presence of thiourea.