Corrosion inhibition effect of 2,8-bis(4-chlorophenyl)-3-hydroxy-4,6-dioxo-4,6-dihydropyrimido[2,1- b][1,3]thiazine-7-carbonitrile (CHPTC) on carbon steel (CS) corrosion in 1.0 M HCl solution was investigated. For this purpose, potentiodynamic polarization, electrochemical impedance spectroscopy (EIS). Polarization studies showed that this molecule act as mixed type inhibitor. Effects of temperature and immersion time on corrosion inhibition were fully discussed. The inhibition action of the pyrimidothiazine derivative was discussed in view of Langmuir adsorption isotherm. The thermodynamic parameters of activation were calculated and discussed. It was found that, CHPTC is a good corrosion inhibitor for the CS corrosion in 1.0 M HCl solution. The inhibition efficiency increased with increasing inhibitor concentration and reached 97.5 % at 1.0×10-3 M CHPTC. The high inhibition efficiency was related to adsorption of CHPTC on steel surface.
