PREPARATION OF NANOSIZED α-ALUMINA POWDER BY PYROLYSIS OF AMMONIUM ALUMINIUM CARBONATE HYDROXIDE

Nanosized α-Al_2O_3 powder is prepared from NH_4Al(SO_4)_2·24H_2O and NH_4HCO_3 through pyrolysis of ammonium aluminium carbonate gydroxide.The influence of pH value on the synthesis of ammonium aluminium carbonate hydroxide is discussed, and the effect of titration rate on the average particle size of nanosized α-Al_2O_3 powder is investigated.By methods of XRD and electron diffraction pattern,crystal form of the sample is proved to be of α-form.Its average particle size is characterized by means of TEM(about 10nm).DZG93-05 method is adopted and the purity of sample is analyzed (99.87%).