M.L. Paramês

Investigation of the microstructure, chemical composition and lateral growth kinetics of TiN films deposited by laser-induced chemical vapour deposition

A study of the laser direct writing of titanium nitride on mild steel substrates by pyrolytic laser-induced chemical vapour deposition was carried out under different operating conditions. Lines of TiN were deposited from a reactive gas mixture of TiCl4, N2 and H2 using a continuous wave TEM00CO2 laser beam as heat source. The deposited material was analysed by optical and scanning electron microscopies, wavelength-dispersive X-ray microanalysis and profilometry techniques. Golden coloured TiN films, close to the stoichiometric composition, were produced exhibiting good adherence, very fine grain size (∼100 nm) and broad gaussian profiles. A time kinetics study based on the lateral growth rate of the deposited lines is also presented. From the transient growth conditions, an empirical relation between the interaction time needed to achieve film deposition and the laser irradiance was established, which led to a value for the incubation period of 5.4 ns. This relation also gave a value for the threshold laser irradiance of 1.54×104W cm−2, in good agreement with the value found experimentally.

Growth of TiC films by thermal laser-assisted chemical vapour deposition

Abstract The kinetics in thermal laser-assisted chemical vapour deposition (LCVD) of titanium carbide (TiC) films and the influence of growth conditions on the structure and morphology of the deposits have been investigated. TiC spots were deposited onto silica substrates using a CW TEM 00 CO 2 laser beam. The reaction gas mixture consisted of TiCl 4 , CH 4 and H 2 and the ratios of the partial pressures of the reactants were varied. The films were analysed by X-ray diffractometry (XRD), micro-Raman spectroscopy, scanning electron microscopy (SEM) and profilometry.

Laser-assisted deposition of TiN and TiC coatings

In this paper we present results on the deposition of titanium nitride and titanium carbide films by pyrolytic laser-induced chemical vapor deposition using a cw TEM00 CO2 laser beam. TiN lines were deposited onto mild steel substrates while TiC spots were deposited on silica substrates. The microstructure of the surface and of fractured cross-sections of the films were examined by scanning electron microscopy. The topography of the films and the thickness measurements were studied both with diamond-stylus and non-contact laser profilometers. The chemical composition of the TiN films was investigated by electron probe microanalysis. X-ray diffraction was used for phase and structure analyses of the TiC films.

Laser Chemical Vapour Deposition of Titanium-Based Hard Coatings

This article is primarily concerned with the laser-assisted chemical vapour deposition (LCVD) of titanium nitride and titanium carbide coatings. The principles of the LCVD technique are briefly outlined and the literature on the LCVD of TiN and TiC films is reviewed. Emphasis is given to the growth mechanisms and to the morphological and structural aspects of the films.