Chemical vapor deposition was used to deposit tungsten carbide from a mixture Of WCl6, H-2 and C3H8 at 750-1050 degrees C on silicon and carbon substrates. The phase composition of the films was correlated with substrate temperature, substrate position in the reactor, and total flow rates. X-ray diffraction and X-ray photoelectron spectroscopy were employed to investigate the surface and bulk properties of the thin films. Thick, adherent films of phase-rich hexagonal WC were deposited using 1.3 x 10(3) Pa total pressure, 1050 degrees C substrate temperature, and reactant flow rates of H-2/C3H8/Ar/WCl6 = 1.8 x 10(-2)/3.6 x 10(-3)/8.9 x 10(-4)/1.8 x 10(-4) mol/min, where Ar is the carrier gas. The surface composition was oxygen and carbon rich as compared with the bulk. (c) 2007 Elsevier B.V. All rights reserved.