سیده نرجس حسینی

In this study, Al2O3/Co nanocomposite was synthesized by mechanochemical reaction between Co3O4 and Al in a planetary high energy ball mill. The mechanism of the reaction in the Co3O4/Al system was studied by using of X-Ray Diffraction (XRD) technique, temperature measurement and thermodynamics calculations. The Co3O4 is found to be reduced by Al through a self-sustaining combustion reaction after the incubation period of 50 min. The results of annealing treatment of powder milled for 12 h indicate that the Al2O3/Co forming reaction during mechanical alloying is irreversible at high temperatures. Although the crystallite size of both ?-Al2O3 and Co phases increases, the nanocomposite maintain the nano-sized grains up to the annealing temperature of 1273 K at an annealing time of 1 h.