Corrosion resistance of pulsed laser modified AZ31 Mg alloy surfaces

Abstract

The effect of laser surface melting on the corrosion resistance of AZ31 Mg alloy in 0.1 M NaCl solution was investigated using different laser processing conditions (energy densities of 14 and 17 J cm−2). Laser treatment induced rough surfaces primarily composed of oxidized species of Mg. XPS analysis revealed that the surface concentration of Al increased significantly as a consequence of LSM. Electrochemical impedance spectroscopy showed that the laser treatment remarkably increased the polarization resistance of the AZ31 Mg alloy and induced a passive-like region of about 100 mV, as determined by potentiodynamic polarization. Analysis of the results obtained provide solid evidence that within the immersion times used in this study, LSM treatment increased the corrosion resistance of AZ31 Mg alloy under open circuit conditions and anodic polarization.

Keywords

• Mg alloys
• laser surface melting (LSM)
• Electrochemical impedance
• Potentiodynamic polarization
• corrosion resistance