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An ultraviolet laser (λ = 266 nm) operated in pulsed mode and a diode laser (λ = 1060 nm) operated in continuous mode were simultaneously applied to create a hybrid laser chemical vapor deposition (CVD) approach. Fine‐grained 3C‐SiC thick films were prepared via hybrid laser CVD by using SiCl4, CH4 and H2 as precursors. The effects of the ultraviolet laser on the preferred orientations, microstructures, microhardness values and deposition rates of 3C‐SiC thick films were investigated. The 3C‐SiC thick films that were prepared at 4 kPa via diode laser CVD exhibited <110>‐orientations and 5‐100 µm grain sizes, whereas those prepared via hybrid laser CVD were randomly oriented with 0.5‐5 µm grain sizes. Compared to diode laser CVD, the additional irradiation of the ultraviolet laser in the hybrid laser CVD improved the Vickers microhardness values of the 3C‐SiC thick films from 30 to 35 GPa, and the maximum deposition rate was also increased from 935 to 1230 µm/h.

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 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.

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