Corrosion inhibition properties of the synergistic effect of 4-hydroxy-3-methoxybenzaldehyde and hexadecyltrimethylammoniumbromide on mild steel in dilute acid solutions

The synergistic effect of the corrosion inhibition behaviour of 4-hydroxy-3-methoxybenzaldehyde and hexadecyltrimethylammoniumbromide on mild steel in 0.5 M H2SO4 and HCl acid test solutions was studied through weight loss measurement and potentiodynamic polarization test. Results show the admixture performed effectively in both acids with inhibition efficiency above 90% in H2SO4 and 80% in HCl acid at all inhibitor concentrations from both tests. Thermodynamic calculations showed the compound chemically adsorbed onto the steel surface forming a protective film. Molecular adsorption followed the Langmuir and Frumkin isotherm models.