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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]

The oxidation behavior of Ti3SiC2 with additive-Al2O3 was studied over the temperature range of 1000–1500 °C in air. Ti3SiC2 based composite has a good oxidation resistance at below 1100 °C. The oxidation kinetics followed a parabolic and a linear law respectively at different oxidation stages. Morphology of oxidation products was observed from the oxidized surface by scanning electron microscope (SEM). Oxides were identified by X-ray diffraction (XRD) and energy-dispersive spectroscopy (EDS). The existence of additive-Al2O3 influenced the morphology of oxides and the oxidation behavior of Ti3SiC2. The formation of pores or cavities at high temperature provided the channels for diffusion of oxygen and accelerated the oxidation behavior of Ti3SiC2 based composite. The effects related to the morphology and microstructure features on the oxidation kinetics are discussed. [Copyright &y& Elsevier]