Abstract
This investigation was made to evaluate the corrosion inhibiting effects of three-component inhibitor for mild steel in HCl. The results were as follows.
(1) One component of the inhibitor, Cu2+, generally accelerates the dissolution of mild steel in acid medium. However, Cu2+ was found to improve the corrosion inhibiting effect under its combination with thiourea and urotropine in suitable ratios.
(2) At low inhibitor concentration, the inhibitor showed the corrosion inhibition of higher than 99%.
(3) At 0.2% inhibitor concentration, the composition of the inhibitor showing the lowest corrosion rate was Cu2+ 0.003%, thiourea 0.057-0.097% and urotropine 0.10-0.14%.
(4) The effect of temperatures on the corrosion inhibition was not observed in the range of 30°C-80°C.
(5) The corrosion inhibiting effect of the inhibitor in H2SO4, H3PO4 or HSO3NH2 was as excellent as in HCl.
(6) The corrosion inhibiting mechanism was further studied by the rapid polarization characteristics.
