IN-DEPTH STRUCTURAL-X-RAY INVESTIGATION OF PECVD GROWN DIAMOND FILMS ON TITANIUM-ALLOYS

Diamond coatings have been deposited in a microwave plasma from CH4-H- 2 and CO-H-2 mixtures, with the aim of improving the wear resistance o f titanium alloys. In-depth distribution profiles of crystalline phase s formed during the diamond films growth are measured here using Grazi ng Incidence X-ray Diffraction (GIXD), in correlation with Scanning El ectron Microscopy (SEM) coupled with EDX analysis. The GIXD method is particularly well adapted to study surface modifications or deposition s of polycrystalline materials. Especially in this case, the formation of different intermediate carbonaceous layers are evidenced in terms of microstructure, from the diamond films to the titanium alloy substr ate. In addition, crystalline parameters, microstrain rates and cohere nt domain size evolutions of different alpha and beta-Ti alloy solid s olutions, titanium carbide and diamond phases have been studied with r espect to grow th kinetics and deposition temperature, at 600 degrees C and 850 degrees C. (C) 1998 Published by Elsevier Science S.A.