Synthesis and characterization of ZnO reinforced zinc matrix composites via in-situ oxidation process

In recent years, biodegradable Zn-based materials have emerged as promising candidates for next generation orthopedic implants owing to their moderate degradability and tailorable functionalities endowed by strategic reinforcement. Herein, Zn-ZnO composites were fabricated via a novel combination of in-situ oxidation and powder metallurgy process. A comprehensive investigation of the microstructure, mechanical performance, degradation behavior, and antibacterial properties was conducted. The microstructural analysis confirmed the homogeneous dispersion of ZnO nanoparticles throughout the Zn matrix, along with strong interfacial bonding. The mechanical tests demonstrated significant enhancement in strength, with tensile yield (ultimate) strength improved from 66.4 MPa (127.4 MPa) to 139.6 MPa (165.2 MPa), while the elongation decreased from 66.0% to 30.0%. The ultimate strength of the sample pre-oxidized at 340 °C reached 171.1 MPa, and the elongation was still over 5.5%. In addition, all composites exhibited controlled degradation rates, where ZnO incorporation accelerated corrosion while promoting Ca/P deposition on the surface. Moreover, ZnO imparted outstanding antibacterial activity, achieving an antibacterial rate of 96.01% for samples pre-oxidized at 280 °C. These findings suggest that ZnO reinforced Zn-matrix composites represent a promising candidate for load-bearing bone fixation applications.