Mechanochemical synthesis of alumina nanoparticles

Abstract: nano- size alumina particles have been synthesized by mechanical activation of a dry powder mixture of alcl3 and cao. mechanical milling of the above raw materials with the conditions adopted in this study resulted in the formation of a mixture consisting of crystalline cao and amorphous aluminum chlorides phases. there was no sign of chemical reaction occurring during milling stage as evidenced by x-ray diffraction studies. subsequent heat treatment of the milled powder at 350?c resulted in the occurrence of displacement reaction and the formation of al2o3 particles within a water soluble cacl2 matrix. the effect of higher temperature calcinations on the phase development in this powder mixture was followed by x-ray diffraction (xrd) analysis and scanning electron microscope ( sem). differential thermal analysis (dta) was used to compare the thermal behavior between the milled and unmilled powders. perhaps the most important result in this study was the observation of alpha-al2o3 phase at a very low temperature of 500c.