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 rea ctive atmosphere consisting of TiCl4, CH4 and H-2. The partial pressur es of the gaseous components were kept constant in all the experiments at 7, 21 and 130 torr, respectively, while the laser power density an d the interaction time were varied in the ranges 90 - 190 W.cm-2 and 1 5 - 40 s. The films were analyzed by X-ray diffraction (XRD), scanning electron microscopy (SEM) and stylus profilometry. In the range of th e deposition parameters investigated, it is shown that preferentially (200) oriented films have been produced. From the profilometric analys es, an apparent activation energy of about 86 kJ/mole for the kinetics of film deposition has been deduced.