Electron beam deposited VC and NbC thin films on titanium: hardness and energy-dispersive X-ray diffraction study

Films of VC and NbC of about 200 nm thickness were electron beam deposited on the sandblasted surface of metallic Ti substrates, preheated at 350 and 500 C, to improve the surface hardness of Ti implants intended for application in orthopaedics. According to both standard angular-dispersive X-ray diffraction measurements and rocking curve analysis performed by energy-dispersive X-ray diffraction, the films were found to be textured preferentially along the (200) crystallographic direction. The (200)-oriented crystallites are randomly rotated around their growth axes, with no correlation among adjacent domains. The measured intrinsic hardness of the films is 24-25 GPa for VC and 18-21 GPa for NbC.