In situ grown Si3N4 microbelt/Mg doped hydroxyapatite dual-layer coating on carbon/carbon composites for biomedical application

A dual-layer coating composed of in situ grown Si3N4 microbelt (SNM) and Mg doped hydroxyapatite (MH) for carbon/carbon composites has been synthesized using a combination method of precursor pyrolysis and electrochemical deposition method. The morphology, microstructure, in vitro bioactivity, bonding strength and corrosion resistance of the coating are analyzed. The results show that SNM exhibits a belt shape and MH shows a flake shape. SNM/MH coating exhibits good bioactivity and suitable bonding strength. SNM/MH dual-layer coating exhibits better corrosion resistance than MH single layer coating. SNM/MH is expected to have potential medical application as coating materials in hard tissue substitution application.