Development of hydroxyapatite-reinforced magnesium matrix composites: Effect of reinforcement ratio on wear and corrosion properties

In this study, magnesium matrix composites reinforced with different weight percentages (1, 3, and 5 wt.%) of hydroxyapatite (HA) were fabricated via powder metallurgy to evaluate their suitability for biomedical applications. The effects of HA content on microstructure, mechanical behavior, wear resistance, and corrosion performance were systematically investigated. SEM and EDX analyses confirmed that while HA was uniformly dispersed at lower concentrations, 5 wt.% HA led to significant particle agglomeration, particularly along grain boundaries. The composite containing 3 wt.% HA exhibited the most favorable properties, including the highest hardness (36.30 HV), lowest wear rate (13.2 × 10⁻³ mm³/m), and significantly improved corrosion resistance (1.00 mm/year). In contrast, the 5 wt.% HA composite showed reduced hardness (29.34 HV), increased wear rate (19.6 × 10⁻³ mm³/m), and a drastic rise in corrosion rate (6.68 mm/year), highlighting the detrimental effect of excessive reinforcement and poor dispersion. These findings demonstrate that a controlled addition of 3 wt.% HA optimizes the balance between mechanical strength, tribological stability, and biodegradation resistance, making it a promising candidate for bioresorbable implant materials.