Sol-gel synthesis of SiC-TiO2 nanoparticles for microwave processing

A novel approach has been explored to facilitate microwave processing of anatase TiO2, a material that is normally inert in a microwave field. This involves production of core-shell silicon carbide ( SiC)-titania ( TiO2) structures in which the SiC exhibits significant microwave loss, and thus a susceptibility to heating via microwave radiation, as well as a high thermal conductivity. SiC nanoparticles were coated with TiO2 using a sol-gel process, involving the hydrolysis of titanium( IV) isopropoxide. Heat treatment of the novel core-shell nanostructure carried out in a conventional furnace and a microwave oven revealed that crystallization of the titania shell to anatase phase occurred at quite different temperatures, viz. 450 degrees C and 190 +/- 10 degrees C, respectively. A range of microstructural and N-2 adsorption/desorption techniques were used to characterize the different materials obtained from the two annealing methods. The relationship between structure and resultant physical properties of these core-shell materials and their behaviour in a microwave field is discussed.