Multi-layer SiC-graphene oxide-hydroxyapatite bioactive coating for carbon/carbon composites

Carbon/carbon composites (CC) coated with hydroxyapatite (HA) applied in bone implant materials could combine the good mechanical properties of CC and excellent biological performance of HA. To further improve the bonding strength between CC and HA, a SiC inner layer and a graphene oxide (GO) intermediate layer were introduced, forming multi-layer SiC-GO-HA coating on CC. The SiC inner layer was fabricated by the pack cementation method. GO intermediate layer was prepared by chemical vapor deposition (CVD) and HNO₃ treatment. HA outer layer was obtained by electrochemical deposition (ECD). The SiC inner layer consisted of hexagonal prisms with 5–10 μm in length wrapped CC substrate completely. GO intermediate layer exhibited a porous network structure with abundant oxygen-containing function groups on the SiC inner layer. SiC-GO-HA coating had a bonding strength of 12.56 MPa with the CC substrate, which increased by 160.58% compared to single-layer HA coating. SiC-GO-HA coating had better anti-corrosive behavior than single-layer HA coating. SiC-GO-HA coating could induce the formation of apatite in simulated body fluid (SBF). SiC-GO-HA coated CC may be the potential for biomedical application.