Chemical Vapor Deposition of Tantalum Carbide from TaCl5-C3H6-Ar-H2 System

Tantalum carbide, which is one of the ultra-high temperature ceramics, was deposited on graphite by low pressure chemical vapor deposition from a TaCl 5 -C 3 H 6 -Ar-H 2 mixture. To maintain a constant TaCl 5 /C 3 H 6 ratio during the deposition process, TaCl 5 powders were continuously fed into the sublimation chamber using a screw-driven feeder. Sublimation behavior of TaCl 5 powder was measured by thermogravimetric analysis. TaC coatings have various phases such as Ta+-Ta 2 C, -Ta 2 C+TaC 1-x , and TaC 1-x depending on the powder feeding methods, the C 3 H 6 /TaCl 5 ratio, and the deposition temperatures. Near-stoichiometric TaC was obtained by optimizing the deposition parameters. Phase compositions were analyzed by XRD, XPS, and Raman analysis.