Abstract This paper presents the corrosion processes of steel samples with different composition, in aggressive corrosion solutions containing chloride ions. The inhibition capacity of two new Mannich basis: 2-aceto-4-morpholylmetyl-1-naphtol (BM1) and 1- (2'-hydroxynaphtyl)-3-(4-morpholyl)-1-propanone (BM2) was tested and compared. The corrosion tests were done in a potentiostatic installation and, based on the polarization curves, the Tafel plots were obtained. The kinetic and thermodynamic parameters (the density of the corrosion current, the mass index, the penetration index and the corrosion potential) were calculated and discussed.