The Chemical Vapor Deposition of Zirconium Carbide onto Ceramic Substrates

Abstract

Zirconium carbide is an attractive ceramic material due to its unique properties such as high melting point, good thermal conductivity, and chemical resistance. The controlled preparation of zirconium carbide films of superstoichiometric, stoichiometric, and substoichiometric compositions has been achieved utilizing zirconium tetrachloride and methane precursor gases in an atmospheric pressure high temperature chemical vapor deposition system. Laminar and equiaxial microcrystalline morphologies were obtained for superstoichiometric and substoichiometric zirconium carbide; respectively, allowing cursory metallographic identification of composition. Observed reductions in film density associated with zirconium carbide films that contain additional free carbon or excess zirconium are reported. These changes in film density were found to be consistent with compositional changes. An apparently linear relationship (correlation of 0.99) between methane flow in this chemical vapor deposition system and zirconium carbide stoichiometry in the substoichiometric range deposited above ZrC0.61 has been observed.

Morphologies and growth mechanisms of zirconium carbide films by chemical vapor deposition

“…ZrC coatings have been grown by electron-beam bombardment, 6 laser cladding, 7 pulsed laser ablation-deposition, 8 magnetron sputter deposition, 9 and chemical vapor deposition (CVD). [10][11][12][13][14][15][16] Among these methods, CVD has advantages over the others in that it could be used to uniformly coat not only flat surfaces, but also complex-shaped components like particles and cutting tools. It therefore is the most investigated deposition method for the preparation of ZrC coatings.…”

Equilibrium analysis of zirconium carbide CVD growth

“…It is noted that the shape of the horizontal phase transition is curved. In atmospheric halide CVD [10,11], the inlet Cl/Zr ratio is 4, so that the condition just inside the ZrC growth zone is shown in Fig. 7.…”

“…Although atmospheric halide CVD using zirconium tetrachloride (ZrCl 4 ), methane (CH 4 ), and hydrogen precursors has produced reasonable quality ZrC films, a relatively high growth temperature is required (1000-2000 1C), thus limiting the list of suitable substrates. Furthermore, halide impurities are incorporated in the film and limit emitter efficiency [10,11].…”

Growth of ZrC thin films by aerosol-assisted MOCVD

“…Although atmospheric halide CVD using zirconium tetrachloride (ZrCl 4 ) and methane (CH 4 ) in H 2 can grow reasonable quality ZrC films, this precursor chemistry requires a relatively high growth temperature (1000-2000 1C), thus limiting the list of suitable substrates [19,20]. Alternatively, the single-source metalorganic precursor tetraneopentyl zirconium (Zr[CH 2 C(CH 3 ) 3 ] 4 , also termed ZrNp 4 ) has been successfully used to grow thin films of ZrC at low temperature (300-750 1C).…”