Evolution of Iron-Based Metallic Glass Composite Coating with Enhanced Corrosion Resistance and Biocompatibility

Metallic glasses are a new class of metallic alloys that attract increasing attention in bone implants due to their ultrahigh wear resistance and hardness, high toughness and superior strength. However, their cytotoxicity and biocorrosion resistance are still under investigation. In this research, the cytotoxicity and biocorrosion resistance of iron-based metallic glass composite coating are explored. To approach real-life conditions, the biocorrosion resistance of the proposed coating in phosphate buffer saline (PBS) is evaluated via immersion test for 30 days followed by an electrochemical corrosion test. Then, human bone cells (MG-63) are cultured on corroded samples and the cell viability is determined using MTT assay, in addition to cell attachment examination. The results revealed the formation of a metallic glass composite layer with 78.76% amorphous content. Additionally, the metallic glass composite demonstrated excellent and stable corrosion resistance in PBS over 30 days compared to the substrate. The MTT assay has shown that the cytotoxicity of iron-based metallic glass composite is within the permitted levels according to ISO 10993-5, Part 5 vol 2009. The cells were well attached to the surface besides, showing a healthy growth after 7 days of culture. These results confirm the in vitro biocompatibility of iron-based metallic glass composite coating for biomedical implant applications.