Papers by Author: Song Zhang

Abstract: Polycrystalline ڂ˽SiC thick film with mm-scaled thickness was deposited on a graphite substrate using a gaseous mixture of SiCl₄ + CH₄ and H₂ at temperatures ranging from 1573 to 1823 K by chemical vapor deposition. Effect of deposition temperature (T_dep) on deposition rate, surface morphology and preferred orientation has been studied. The preferred orientation changed from <111> to <110> with increasing T_dep. The maximum deposition rate (R_dep) of 1125 ڌ̽˰̸⁻¹ has been obtained. The surface morphology has changed from six-fold pyramid to five-fold facet with increasing T_dep.

Abstract: Thick (over 1 mm) β-SiC films were deposited at a deposition temperature of 1823 K and a total pressure of 4 kPa by halide CVD using SiCl₄ and CH₄ as precursors, and H₂ as carrier gas. The maximum deposition rate was 1125 μm h⁻¹. The SiC films showed strong (220) preferred orientation. The grain size increased from 20 to 100 μm with increasing C/Si ratio.

Abstract: A group of boron-carbon ceramic material was in-situ synthesized and densified simultaneously via Spark Plasma Sintering (SPS) technique from carbon and boron element powders with different molar ratio. The phase structures of samples with different B/C molar ratio were characterized by X-ray Diffraction (XRD). The B/C atomic ratio of the sintered materials was calculated from X-ray photoelectron spectroscopy (XPS) measurement data. Meanwhile, the chemical analysis (CA) method had also been taken to verify the B/C atomic ratio. Finally, the experience equation had been obtained to control the B/C atomic ratio of sintered samples.