Hydroxyapatite and bioactive glass composite coating on Ti-6Al-4V

Hydroxyapatite (HA) was widely used as coating on metals and alloys to enhance the interconnection between metal implants and bone. To improve the bonding strength and bioactivity, in this work, bioactive glass (G) was added and HA-G composite coating was prepared on Ti-6Al-4V at low temperature. The scanning electronic microscope (SEM) graphs showed that the surface of the coating was composed with needle-like crystals, and the X-ray diffractometer (XRD) and Fourier transform infra-red spectrometry (FTIR) results proved that the crystals was carbonate hydroxyapatite (CHA), no other crystal phase was detected. The SEM micrographs of the cross section showed that the coating was porous and bonded closely with the surface of the alloy. The energy diffraction spectra (EDS) result show that a Si-Ti-Al-V-0 layer was formed at the interface and enhance the interconnection between the coating and alloy. The bonding strength of the coating was 34.8 plus/minus 6.8MPa, which was much higher than that of the pure HA coating on Ti-6Al-4V prepared by plasma spraying method. The HA-G composite coating on Ti-6Al-4V showed high bonding strength, porous structure, and bone like CHA composition, which has good potential to be used as bone substitutes.