A new class of Ti-Si-C-N coatings obtained by chemical vapor deposition - part II: low-temperature process

A new class of the Ti-Si-C-N coatings obtained by chemical vapor deposition with TiCl4, SiCl4, C2H2, H-2, and N-2 as reactants have been further examined in this study. The effects of deposition temperatures have been explored in the range of 700-1100 degreesC. The resulting deposits have a non-stoichiometric TiC structure as a (Ti,Si)(C,N) solid solution. Large, dense, well-crystallized, and faceted crystals with a hardness value of similar to 10 GPa can be obtained at deposition temperature as low as 800 degreesC. The Si content is barely detectable in the coatings deposited at 800 degreesC, but increases as the deposition temperatures increase from 800 to 1100 degreesC. Coatings of a hardness value of 27.5 GPa are obtained for a coating deposited at 1100 degreesC. Furthermore, the effects of TiCl4 and SiCl4 flows at a deposition temperature of 800 degreesC have also been studied. The data for growth rate and composition can be best described by the absorption/surface coverage behavior and the relatively low reactivity of SiCl4 at low temperatures. Finally, the effects of H-2 and N-2 at deposition temperature of 800 degreesC have been studied. Deposits form at higher H-2 input and improve when sufficient N2 is also added. (C) 2001 Elsevier Science B.V. All rights reserved.