Preparation and characterization of nanometer-sized α-Al_(2)O_(3) powders

Nanometer-sized α-Al_(2)O_(3) powders were prepared by both solid-phase method and wet-chemical methods with (NH_(4))_(2)SO_(4)·Al_(2)(SO_(4))_(3)·24H_(2)O as raw material and soluble starch as dispersent.The prepared powders were treated by ultrasonic waves.XRD analysis showed that the powders were α-Al_(2)O_(3),and the sizes of the particals were observed about 20nm～30nm through TEM analysis and their shapes were ball-like.In the experiments,the space obstruct of long molecular chain,the separation of the polymer-network and the physical dispersion of the solid dispersent were used to inhibit the aggreagte of Al_(2)O_(3) powders.Compared with sol-gel,aluminium alcoholate-hydrolysis and ficroemulsion methods,the solid-phase method has advantage of simple process,low cost of production and stable quality of product.So it is suited for industrial produce.The development of this technology is a solid basis for the preparation of nanometer-sized mesoporous α-Al_(2)O_(3),which is the coating material on printing ink-sprayed paper for photograth.