The heterocyclic anils 2-salicylideneaminobenzothiazole (SABT), 2-salicylideneamino-6-chlorobenzothiazole (SACLBT), and 2-salicylideneamino-6-methoxybenzothiazole (SAMEOBT) were investigated to evaluate their efficiency as corrosion inhibitors for mild steel (MS) in 1 M hydrochloric acid (HCl) at concentrations from 100 ppm to 500 ppm and temperatures from 35°C to 60°C. SACLBT performed best, giving an inhibition efficiency as high as 98% even at a very low concentration and higher temperature. Potentiodynamic polarization studies showed inhibition was under cathodic control. These compounds reduced hydrogen permeation through MS in 1 M HCl solution. Adsorption on the MS surface 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, sulfur, and chlorine atoms with the metal surface.

Subject
Acids, Chemical compounds, Hydrogen permeation, Metal surfaces, Adsorption, Adsorption isotherms, Permeation current, Solutions, Film formation, Inhibition efficiency, Corrosion inhibitors, Cathodic inhibitors, Potentiodynamic polarization
Keywords:
acid environments, anils, auger electron spectroscopy, chloride, hydrochloric acid, hydrogen permeation, inhibition efficiency, mild steel, potentiodynamic polarization testing, Temkin’s adsorption isotherm
NACE International
1997
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