Morphological Aspects of SiC Obtained by Microwave Carbothermal Reduction of Dry Sugarcane Chaff

摘要

The precursors for the carbothermal reaction were obtained from the burning of the sugarcane chaff. The obtained ash was treated with HNO3 to remove part of the impurities and residual organic matter. The chemical treated ash were blended with carbon black and extruded in the form of pellets. The reactions were performed in a semi-industrial microwave oven. The morphological features of the samples were evaluated by XRD and SEM. XRD results indicated that SiC was the primary phase formed in the reaction, although a minor amount of calcium-based phases were also present. The micrographs of the synthesized samples revealed that the samples processed using helium as gas atmosphere presented large plate particles with angular corners and presenting hexagonal shapes with well-defined edges, while the powder obtained using nitrogen as gas atmosphere have the morphology of soft agglomerates constituted by fine particles, which have diameters on the range of sub-micrometric sizes.