EFFECT OF PULSED LASER ABLATION IN WATER ON THE CORROSION BEHAVIOUR AND SURFACE HARDNESS OF STAINLESS STEELS

Abstract

This work presents the use of pulsed fibre laser ablation in water (PLAW) to study the corrosion behaviour and surface hardness of stainless steels. A stainless-steel plate was ablated with a pulsed ytterbrium-doped fibre laser at a power of 4.2 W. The laserablated sample was subjected to corrosion testing using electrochemical impedance spectroscopy and potentiodynamic polarisation. The results correlated with surface morphology, X-ray diffraction profiles and Vicker’s hardness values. PLAW can enhance the corrosion resistance of stainless steels in both neutral and acidic electrolytes. The corrosion potential of the lasertreated samples was more positive at −126 and −423 mV compared with that of the as-received samples at −209 and −439 mV in neutral and acidic electrolytes, respectively. The inhibition efficiencies of the laser-treated samples in neutral and acidic electrolytes were 98% and 52%, respectively. An improvement in the surface microhardness at a maximum of 8.7% was reported on the fibre laser-ablated stainless steels, thereby demonstrating the efficiency of fibre-laser-assisted PLAW in inhibiting corrosion and improving the hardness of stainless steel.