Characterisation of smooth fine-grained diamond coatings on titanium alloy by TEM/EELS, Raman spectroscopy and X-ray diffraction

Smooth fine-grained diamond (SFGD) coatings have been deposited by a two-step microwave PACVD process on titanium alloys at 600 °C. The first step consists in depositing, from a methane-rich CH4–H2 mixture, a sacrificial sp2-carbon containing layer that can diffuse partly or completely during the diamond growth which is carried out in a second step from a CO2–CH4 inlet mixture. The coating microstructure and carbon hybridisation state were …