Effect of laser treatment on morphology and corrosion behaviour of the plasma electrolytic oxidation coatings developed on aluminized steel

Abstract

The present study focusses on laser surface modification of the plasma electrolytic oxidation (PEO) coatings developed on aluminized steel. The effect of varying laser fluency on the surface morphology and the corrosion behaviour of the PEO coatings was studied. Three different laser fluencies of 38.16, 53.42 and 68.69 J/cm2, corresponding to the 25%, 35% and 45% of the maximum power (60 W) were employed for the surface alteration. Laser treatment of the PEO coatings at lower and intermediate fluencies resulted in the development of a hydrophobic surface, thereby improving the corrosion resistance, whereas the laser treatment at higher fluency has resulted in the hydrophilic surface, with reduced corrosion resistance. The PEO sample laser-treated with intermediate fluency has produced a superhydrophobic surface with a contact angle of 153.2°. Potentiodynamic polarization (PDP) studies revealed that the PEO coated aluminized steel sample, laser-treated with intermediate fluency, exhibited superior corrosion resistance with a corrosion current density (icorr) of 1.21E−6 mA/cm2, which is 104 times lower than the aluminized steel.