TiC_xN_y and TiC_x-TiN films obtained by CVD in an ultrasonic field

Abstract

TiC _x N _y mono- and TiC_x-TiN double-layer films with a thickness of 30 to 100 μm were prepared on a carbon steel (C: 0.6 to 0.7%) substrate by CVD in an ultrasonic field (ultrasound frequency: 19kHz; power: 10 to 20Wcm⁻²). The moderate deposition conditions for obtaining an adherent and thick film of TiC _x N _y were: substrate temperature: 1050° C; H₂, N₂, TiCl₄ and CH₄ flow rates: 6.2, 4.0, 0.9 and 0.26 to 2.0 ml sec⁻¹, respectively. The growth rate, grain size and degree of 〈2 2 0〉 preferred orientation were found to decrease with increase in CH₄ concentration. TiC _x N _y film on carbon steel had a Vickers microhardness of 1800 to 2600 and an adhesion strength to the substrate of more than 120 kg cm⁻². A TiC _x -TiN (x∼0.5) double-layer film was obtained at 1050° C by a controlled alternative deposition of TiC _x or TiN. Quasiepitaxial growth of crystallites in the double layers was found to prevail in both coatings of TiC _x (220)/TiN (220)/steel and TiN (200)/TiC_x (200)/steel.