Investigating PLGA/HA composite coating for improved corrosion resistance and mechanical integrity of biodegradable Mg alloys
Navdeep Singh Grewal, Ahsan Tareen, Kamal Kumar, Neeraj Ahuja
Abstract
Magnesium (Mg) alloys are promising biodegradable materials for next-generation orthopaedic implants; however, their rapid degradation and early mechanical failure in physiological environments hinder clinical translation. In this study, a PLGA/HA composite coating was developed on the AZ31 Mg alloy via the sol-gel dip-coating technique to overcome these limitations. The uncoated AZ31 exhibited an Ecorr of −1.44 V and Icorr of 8.30 × 10−4 A cm−2, while the coated sample showed an improved Ecorr of −0.72 V and a reduced Icorr of 4.46 × 10−6 A cm−2, corresponding to a ten-fold decrease in corrosion rate. Hydrogen evolution rate was limited to 0.16 mL cm−2 day−1, and pH remained near-physiological (7.46), confirming the coating's corrosion-suppression ability. After 21 days in SBF, the coated samples retained 74% of their ultimate compressive strength and 89.5% elongation, demonstrating preserved mechanical integrity. These findings support the potential of PLGA/HA coatings in enhancing the durability and biocompatibility of Mg-based bioimplants.