INFLUENCE OF HETEROCYCLIC ANILS ON CORROSION INHIBITION AND HYDROGEN PERMEATION THROUGH MILD-STEEL IN ACID CHLORIDE ENVIRONMENTS

The heterocyclic anils 2-saIicylideneaminobenzothiazole (SABT), 2-sali cylideneamino-6-chlorobenzothiazole (SACLBT), and 2-salicylideneamino- 6-methoxybenzothiazole (SAMEOBT) were investigated to evaluate their e fficiency as corrosion inhibitors for mild steel (MS) in 1 M hydrochlo ric acid (HCl) at concentrations from 100 ppm to 500 ppm and temperatu res from 35 degrees C to 60 degrees C, SACLBT performed best, giving a n inhibition efficiency as high as 98% even at a very low concentratio n and higher temperature. Potentiodynamic polarization studies showed inhibition was under cathodic control. These compounds reduced hydroge n permeation through MS in 1 M HCl solution. Adsorption on the MS surf ace followed Temkin's adsorption isotherms, Surface analysis of the MS surface exposed with SACLBT proved adsorption of this compound on the surface occurred through interaction of lone pairs of nitrogen, sulfu r; and chlorine atoms with the metal surface.