Fabrication of an Ultra-Thick-Oriented 3C-SiC Coating on the Inner Surface of a Graphite Tube by HHH-CVD

摘要： 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 (HHH-CVD) using SiCl4, CH4, and H2 as precursors. The texture coefficient (TC(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, TC(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.