Apatite formation and weight loss study in EDMed perforated AZ31 Mg-alloy

Porous structures are highly preferred for bone regeneration and high tissue in-growth. In present work, electrical discharge drilling (EDD), a thermal erosion process was used to produce through holes in Mg-alloys to fabricate perforated structure similar to open cell porous structure in extruded AZ31. Apatite formation and weight loss study was conducted for 7 days, 14 days and 21 days after immersion tests in SBF solution. The perforated structure in AZ31 with 26 through micro-holes provides 72% increase in surface area but with marginally 4% higher weight loss as compare to non-perforated structure. Comparing perforated and non-perforated samples of Mg-alloy, it was well observed that perforated structure forms high volume of apatite as compared to non-perforated structure. Scanning electron microscopic (SEM) study revealed that in perforated structure, drilled holes retain their circularity after 21 days of immersion test and distinct corrosion phenomenon occur at localized sites.