Optimization of the Parameters Influencing the Control of Dual-Phase AISI1040 Steel Corrosion in Sulphuric Acid Solution with Pectin as Inhibitor Using Response Surface Methodology

In this work, AISI1040 steel specimens have undergone appropriate heat treatment schedules for the development of ferrite-martensite and ferrite-bainite microstructures. The role of martensite and bainite on corrosion rate and inhibition efficiency was investigated through weight loss experiments in a 0.5 M H2SO4 solution. The effect of various parameters on the corrosion behavior of two types of dual-phase AISI1040 steel has been examined. The investigation of the surface morphology of the samples was accomplished with the presence and absence of a pectin inhibitor. The experimental design was performed with Minitab 19 software and the response surface method and desirability function approach was used to reduce the number of experiments and identify locally optimized conditions for the study parameters. From the results, it was observed that the concentration of inhibitor is having the highest influence on the inhibition efficiency (with 39.38 and 69.67% contribution) followed by temperature and immersion time. Surface studies confirmed corrosion and its intensity on the metal surface as the surface became remarkably rough following exposure to the corrosive medium. The maximum inhibition efficiency of 74.02 and 80.35% is observed for a specific set of parameters for dual-phase ferrite-martensite and ferrite-bainite AISI1040 steel. From the results, it was also observed that lower weight loss and better inhibition efficiency are achieved in the case of ferrite-bainite when compared to the ferrite-martensite microstructure.