Chemical vapor deposition of TiWC thin films

TiWC thin films were deposited on stainless steel substrates (440C) by chemical vapor deposition (CVD) in a horizontal hot-wall reactor from a TiCl4W(CO)6CH4H2Ar gaseous mixture, at 1323 K and at pressures ranging from 0.13 to 20.00 kPa. The structures of the TiWC thin films were characterized using X-ray diffraction (XRD). The lattice constant of the TiWC films shifts from that of TiC to WC1−x with increasing W concentration in the thin films. A morphological analysis was carried out using scanning electron microscopy (SEM). It was found that the surface morphology varied with the W concentration and total flow. Compositional studies and binding characteristics in the TiWC films were investigated by X-ray photoelectron spectroscopy (XPS). The associated hardness measured by nano-indentation ranged from 23 to 32 GPa. The studies of transmission electron microscopy (TEM) and selected area diffraction (SAD) reveal the detailed microstructure of the TiWC thin films and the presence of a WC phase.