ABSTRACT
The effects of inhibitors on corrosion of low carbon steel in hydrochloric acid pickling solution was investigated by weight loss and hydrogen evolution measurements using a beaker-funnelburette arrangement. Corrosion and hydrogen evolution rates were computed for steel samples immersed in hydrochloric acid pickling solutions with the addition of varying concentrations of organic (formaldehyde, acetaldehyde. and benzaldehyde) and inorganic (sodium dichromate and sodium nitrite) inhibitors. The organic compounds inhibit both the corrosion and hydrogen evolution rates while the inorganic salts stimulate the corrosion but inhibit hydrogen evolution rate. Acetaldehyde showed the highest inhibition efficiency. Inhibition by the organic compounds could be attributed to adsorption phenomena while corrosion stimulation by the inorganic salts was due to their inability to form stable passivating film on the steel surface.