Microstructural, mechanical, corrosion, and biological behavior of spark plasma sintered commercially pure zinc for biomedical applications

Abstract

This study investigates the microstructural, mechanical, corrosion, and biological behaviors of spark plasma sintered (SPS) zinc (Zn) samples for biomedical applications. The findings reveal that SPS significantly refines the grain structure of pure Zn compared to the conventional casting method. The SPS process, conducted at a lower sintering temperature of 300 °C and a high uniaxial pressure of 50 MPa, produces fine and uniform equiaxed grains with an average size of 19 μm. The resulting Zn samples exhibit a calculated density of 7.1 g cc⁻¹ due to complete densification. The sintering process disrupts the initial texture strength, and the uniform grain orientation achieved during SPS contributes to an isotropic microstructure, enhancing the mechanical properties. The compressive yield strength and ultimate strength of the SPS samples are 115 ± 4 MPa and 191 ± 6 MPa, respectively. The long-term biodegradation behavior of SPS Zn in simulated body fluid indicates controlled and gradual corrosion, supporting its potential for biodegradable implant applications, while potentiodynamic polarization analysis further confirms similar corrosion rates compared to cast Zn due to the formation of a stable corrosion product film. In vitro studies with MC3T3-E1 preosteoblast cells show healthy proliferation in culture media containing the degradation products of SPS Zn. Due to its unique microstructural, mechanical, and corrosion properties, along with its biocompatibility, SPS-processed Zn is a promising candidate for tissue engineering applications.