Biodegradable Mg-Zn-MgO Composites for Locking Compression Fixation Plates for Pediatric Orthopedics: Improved Mechanical Properties and Corrosion Resistance

Biodegradable magnesium-based composites show potential application in orthopedic implants, with excellent biocompatibility, low density, and biodegradable characteristics inside the human body. In this study, the stir casting procedure was employed to produce magnesium–zinc MMCs (metal matrix composites) reinforced with MgO nanoparticles, and they were characterized intensively. The analyzed compositions were Mg/4Zn, Mg/4Zn/0.4MgO, and Mg/4Zn/0.6MgO. Their mechanical properties, corrosion resistance, and microstructure were then investigated employing tensile, impact, hardness, wear, and corrosion tests, supplemented with SEM analysis. The results indicate that the Mg-4Zn-0.6MgO composite exhibited the highest performance among the tested formulations, with a tensile strength of 150 MPa, a hardness of 65 HRE (Rockwell Hardness, E-scale), and enhanced corrosion resistance. These improvements are attributed to the uniform dispersion of MgO nanoparticles and the formation of a protective Mg(OH)2 layer, which together contribute to mechanical reinforcement and controlled degradation behavior. The combination of superior mechanical properties and customizable biodegradability verifies the engineered Mg/4Zn/0.6MgO composite as a promising candidate for a biodegradable orthopedic fixation plate without secondary surgery.