Microhardness Assessment of Magnesium Alloy after Powder Mixed Wire Electrical Discharge Machining and Hydroxyapatite Coating

Abstract

Magnesium (Mg) alloys, which have excellrnt biocompatibility and characteristics similar to bone, are ideal choices for temporary biodegradable othopedic implants. However, because of their low ductility and fast corrosion, their applicability in biological environments is currently limited. Surface properties can be altered by surface treatments such as coating, alloying, and mechanical working to make it application friendly. In this experimental study, ZE41A Mg alloy was processed with powder mixed wire electric discharge machining (PMWEDM) and hydroxyapatite (HA) coating, to analyse their effect on microstructure and micro-hardness. Surface microstructure of parent, PMWEDMed, and HA-coated samples was analyzed by using Field emission scanning electron microscopy (FE-SEM). The microhardness (MH) of these samples was determined using a Vickers micro-hardness tester before and after 14 days of immersion in simulated body fluid (SBF). The results show that PMWEDM and HA coating produced surfaces with higher MH. The post-immersion data show a loss of MH in all three types of Mg samples, which is attributed to sample degradation in SBF.