Effects of Laser Ablation Parameters to Pattern High Purity Magnesium Surfaces

Magnesium and magnesium-based alloys have relatively low weight and desirable mechanical properties for many applications in multiple industries including aerospace and automotive. In the past decade, due to its biocompatible nature, the medical field has expressed significant interest in magnesium for biodegradable implant applications. However, utilization of magnesium-based alloys in surgical implant applications is strictly limited by magnesium’s high vulnerability to corrosion causing premature disintegration inside the human body. Hydrophobic (non-wetting) behavior of metal surfaces has been proven to be beneficial for corrosion protection in academic literature. One way of achieving hydrophobic and super-hydrophobic surfaces on metal surfaces without using non-biocompatible coatings is creating uniform microstructures that would alter the wetting characteristics of the surface. This work focuses on creating uniform pillar shaped micro-patterns on smooth pure magnesium surfaces by utilizing a picosecond laser (λ = 355 nm). The study reports the effects of average laser power, partial laser beam overlap and number of laser scans on the height, steepness, roughness of the resultant micro-pillars. Information gathered from this study could be useful in creating more complex or finer micro-structures on magnesium and its alloys to alter their wetting or corrosion characteristics using laser ablation which is a fast, repeatable and an un-convoluted process.