Preparation and characterization of porous zinc prepared by spark plasma sintering as a material for biodegradable scaffolds

Abstract

Recently, zinc-based materials have been extensively investigated as materials suitable for the fabrication of biodegradable orthopedic implants. In this study, porous zinc was prepared as a material for implantation into trabecular bone using spark plasma sintering with different sizes of initial zinc powders, and microstructural, mechanical and corrosion characterizations of the prepared materials were performed. The porosity of the prepared porous samples was approximately 20%. The mechanical properties depended on the initial powder particle size, the pore size and distribution. By using a finer powder (FP), <100 μm in size, the compressive yield strength and the compressive modulus were approximately 31.2 MPa and 1.2 GPa, respectively. These values approach those of trabecular bone (1–12 MPa and 0.1–0.4 GPa). Moreover, the plastic deformation of FP materials occurred at almost constant stress similar to trabecular bone. The corrosion rates of the porous Zn were 0.6–0.8 mm/a and depended on the initial powder particle size, the pore size and distribution. After pre-incubation of the porous Zn in simulated body fluid (SBF), the Zn concentration in biological extracts was below the toxic limit of zinc for L929 cells. Based on the obtained results, we can estimate that the materials prepared from the finer zinc powder showed properties suitable for the fabrication of porous biodegradable orthopedic implants.