Microstructure, mechanical and corrosion properties of hot-pressed graphene nanoplatelets-reinforced Mg matrix nanocomposites for biomedical applications

Abstract

Owing to their natural ability to degrade in the body, magnesium (Mg)–based alloys and composites are attracting significant attention as candidate materials for various orthopedic and cardiovascular applications. Due to their potential ability to enhance the mechanical strength and corrosion resistance of Mg matrix nanocomposites (MMNCs), graphene nanoplatelets (GNPs) are considered a promising reinforcement for MMNCs. However, the optimum GNP content and fabrication process to obtain high mechanical strength and corrosion resistance for MMNCs are still not clear. This study has investigated the mechanical and corrosion properties of MMNCs reinforced with 0.1–0.3 wt% GNPs fabricated via hot pressing of Mg and GNP powder mixtures prepared by ball milling. Results indicate that the addition of 0.1–0.3 wt% GNP reinforcement to MMNCs resulted in increases in both the ultimate compressive strength and the compressive yield strength. Electrochemical and hydrogen evolution tests in Hanks’ Balanced Salt Solution showed that the corrosion rates of the MMNCs significantly decreased due to the addition of GNPs. Increased GNP addition from 0.1 wt% to 0.3 wt% in the MMNCs led to decreases in the release of Mg2+ ions by 25%, 41%, and 48%, respectively, during their degradation in HBSS as compared to pure Mg. Based on these results, hot-pressed MMNCs can be considered candidate materials for biomedical applications.