STRUCTURE AND MORPHOLOGY OF LASER-ASSISTED CHEMICAL-VAPOR-DEPOSITED TIC COATINGS

Titanium carbide has been deposited on silica substrates by pyrolytic laser chemical vapour deposition (LCVD) using a cw CO2 laser and a reactive atmosphere consisting of TiCl4, CH4 and H-2. The partial pressures of the gaseous components were kept constant in all the experiments at 7, 21 and 130 torr, respectively, while the laser power density and the interaction time were varied in the ranges 90 - 190 W.cm-2 and 15 - 40 s. The films were analyzed by X-ray diffraction (XRD), scanning electron microscopy (SEM) and stylus profilometry. In the range of the deposition parameters investigated, it is shown that preferentially (200) oriented films have been produced. From the profilometric analyses, an apparent activation energy of about 86 kJ/mole for the kinetics of film deposition has been deduced.