DIFFUSE-REFLECTANCE INFRARED FOURIER-TRANSFORM STUDY OF THE DIRECT THERMAL FLUORINATION OF DIAMOND POWDER SURFACES

The direct thermal interaction of elemental fluorine with (i) hydrogen ated and (ii) oxidized diamond surfaces has been investigated by diffu se reflectance infrared Fourier-transform (DRIFT) spectroscopy. The hy drogenated diamond surface is fluorinated by thermal reaction with ele mental fluorine. Hydrogen chemisorbed on the diamond surface is abstra cted by the reaction with fluorine molecules at -10 degrees C. Peaks d ue to C-F stretching vibrations are observed at 1098, 1251 and 1360 cm (-1) after the fluorination of the hydrogenated diamond. The oxidized diamond surfaces are affected by elemental fluorine. Peaks due to C=O stretching vibrations on the oxidized diamond surfaces remained and sh ifted toward the higher wavenumber region as the temperature was decre ased below 400 degrees C. The fluorination of the oxidized diamond at 500 degrees C gave similar chemisorbed states of fluorine compared wit h those of the hydrogenated diamond.