Location via proxy:   [ UP ]  
[Report a bug]   [Manage cookies]                

Influence of Substrate and Process Parameters on the Properties of CVD-SiC

MRS Fall Meeting, Boston, USA, 29 November - 2 December, 1989, 1989
The microstructure and mechanical properties (adhesion, hardness) of beta-SiC coatings, prepared in a cold-wall reactor, were studied by examining different substrates and deposition process conditions. Hard (3500 HK), fine grained beta-SiC coatings were deposited onto graphite at relatively high deposition temperatures (1473-1673 K) using SiCl4, C3H8, H2 gas mixtures. The thermal decomposition of methyltrichlorosilane (MTS) in hydrogen and argon allowed the production of beta-SiC coatings onto a variety of substrate materials in the temperature range 1173-1373 K. The growth mechanisms of SiC deposited from MTS/H2/Ar system onto graphite and polycrystalline alfa-SiC substrates were studied. At low (40 kPa) and atmospheric pressure, the growth kinetics is limited by surface reactions. Also, a strong dependence of the microstructure and crystallographic orientation on the deposition parameters was observed. Hard metals (WC/Co) were successfully coated with beta-SiC using the MTS/H2/Ar system. Problems of chemical compatibility between the substrate and the beta-SiC coating were minimized by the deposition of an intermediate TiN layer....Read more