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The reactivity of HO and the Si-terminated silicon carbide surface (001) was investigated on the triplet potential energy surface with the combined first principle and molecular mechanics ONIOM(CASSCF:AM1:UFF) method for the (SiC)·HO model. It was found that the HO molecule and the surface can form three physisorption complexes and follow five reaction paths to produce eight products, in which there are five main products having necessary energy barriers less than 300 kJ mol. Compared with that on the C-terminated surface, the interaction with the Si-terminated surface has stronger physisorption energy, smaller lowest necessary energy barrier, more main and more stable products. [ABSTRACT FROM AUTHOR]

Viscous flow behavior of silica melts on an uncooled carbon/silicon carbide composite nozzle was investigated in the combustion environment of a liquid-fueled rocket engine simulated by an ethanol/oxygen combustion gas generator. The results showed that severe ablation of the nozzle throat were attributed to flow downstream and blow-off of the silica scales derived from vigorous oxidation of the silicon carbide matrix. The viscous flow behavior of the silica was determined by both the intrinsic viscosity of silica melts and the external aerodynamic forces of the combustion gas. [ABSTRACT FROM AUTHOR]

Structural, electronic and mechanical properties of the nH-SiC (n = 2, 4, 6, 8 and 10) polytypes are calculated by using the first-principles calculations based on the density-functional theory approach. The optimized lattice parameters of nH-SiC are in good agreement with the experimental data. The mechanical properties, including elastic constants, bulk modulus, Young's modulus, shear modulus and Poisson's ratio, are calculated. The analysis of elastic properties indicates that the effects of n on the mechanical properties of the five nH-SiC structures have no difference. The indirect band gap relationship for the five polytypes is Ebg2H > Ebg4H > Ebg6H > Ebg10H > Ebg8H. [ABSTRACT FROM AUTHOR]