Developing Al2O3-TiC in-situ nanocomposite by SHS and analyzingtheeffects of Al content and mechanical activation on microstructure

摘要

Al2O3-TiC in-situ nanocomposite was developed by self propagating high temperature synthesis (SHS) process using TiO2, Al and C powders as starting materials. The effects of mechanical activation and Al content on the reaction mechanisms and microstructures of products were investigated and thermodynamic and kinetic aspects of reactions were evaluated. Samples were characterized by X-Ray diffraction (XRD), scanning electron microscopy, (SEM)and Energy Dispersive Spectroscopy (EDS) According to the flndings,increasing Al content of reactants led to enhancing the heat transfer and avoiding heat outlet bv omitting CO as gas product. Also,mechanical activation resulted in better distribution of the initial materials, a decrease inthe diffusion distance, and in better kinetics of the combustion synthesis reaction at lower temperature. Consequently, ceramic matrix nanocomposites (CMNC) with phase size less than 800 nm and crystalline size less than 65 nm were developed.