Laser Patterned Hydroxyapatite Surfaces on AZ31B Magnesium Alloy for Consumable Implant Applications

Abstract Currently, materials employed for use as consumable prosthetic devices possess uncontrolled degradation via corrosive action and inferior bio-integration characteristics. A material that is biocompatible and mechanically rigid is necessary for osseointegration. In an attempt to address these issues, a novel laser surface engineering approach was used to produce physically patterned hydroxyapatite coatings on the magnesium AZ31B alloy. Variations of two different laser processing parameters, namely laser power (800-1200 W) and laser track separation (0.15-0.9 mm), were explored in conjunction to determine the optimal processing combination. Biocompatibility was subsequently examined via contact angle measurements and performing in-vitro immersions in simulated body fluid. The surface characteristics, microstructure, and phase evolution of post-processed and post-immersed samples were examined using optical profilometry and scanning electron microscopy.  It was confirmed that samples with hydrophilic contact angles correlated to higher degrees of biomineralization and minimal corrosion. These hydrophilic contact angles were realized in samples processed either with low laser power and a higher degree of track overlap or with high laser power and no laser track overlap.