CVD diamond films on bio-medical ceramics

Abstract

In this study, the growth of diamond films by the hot filament chemical vapour deposition method on ceramic substrates is presented. The ceramics, used in teeth implants, were sintered at 970 °C, and were mainly constituted by SiO 2 , Al 2 O 3 and other oxides. To avoid substrate damaging, the diamond deposition was carried out at a lower temperature than usual. Raman spectroscopy demonstrated the growth of polycrystalline diamond films with a very low content of amorphous carbon phases at a temperature as low as 750 °C. The thermal expansion mismatch between film and substrate causes the films thicker than 0.2 μm to break, but the high nucleation density of diamond obtained when the ceramic was scratched with diamond powder allowed the formation of compact and well-adhered diamond films, even with this small thickness. Optical analysis of the reflection spectra of the coating in the visible range, when compared with the spectra of the bare ceramic, showed that diamond films do not appreciably affect the reflection of light.