Fabrication of an ultra-thick-oriented 3C-SiC coating on the inner surface of a graphite tube by high-frequency induction-heated halide chemical vapor deposition

Cubic SiC (3C-SiC) is a promising material for nuclear industry applications due to its excellent properties. In this report, a highly oriented thick 3C-SiC coating with good crystallinity was prepared on the inner surface of a monolithic graphite tube via high-frequency induction-heated halide chemical vapor deposition using SiCl ₄ , CH ₄ , and H ₂ as precursors. The texture coefficient (T _{C (hkl)} ), microstructure, and deposition rate along the tube axis was studied. 3C-SiC coating with a high (111) orientation and crystallinity was obtained. Along the tube axis, T _{C (111)} was consistent with the temperature distribution. The surficial morphology of the 3C-SiC coating changed from pebble-like to hexangular facet and then to hemispherical. The deposition rate and coating thickness were 300 μm/h and 615 μm, respectively, which is sufficiently rapid and thick enough to obtain free-standing SiC tubes for nuclear reactors.