Electrochemical studies of corrosion inhibition of a series of quaternary ammonium salts on iron in HCl solution

THE INHIBITION and the effect of concentration of a series of quaternary ammonium salts I on corrosion of iron in 1M HCl solution were electrochemically studied. These inhibitors were: tetramethylammonium bromide, tetraethylammonium bromide, tetrapropylammonium bromide, tetrabutylammonium bromide, tetrapentylammonium bromide, tetrahexylammonium bromide and tetraheptylammonium bromide. The concentration of the inhibitors ranged from 1x10(-6)M to 1x10(-2)M. It was concluded that the percentage inhibition increased with the increase of the concentration in each inhibitor and with the increase of the chain length of the alkyl substituent. The efficiency of corrosion inhibition ranged from 85.55% with 1x10(-2)M tetramethylammonium bromide and 99.46% with 1x10(-2)M tetraheptylammonium bromide. Furthermore, it was found that the degree of inhibition for all the inhibitors closely followed the adsorption isotherm of the inhibition on the metal surface.