A grinding process is well known for size reduction of a bulk material. However, the efficiency of the method is limited and not considerable. In this study, a simple method is proposed for reducing the particle size of nano-crystalline alumina powder. The principle of the procedure lies in a localized etching caused by the chlorine released from molten aluminum tetra chloride. In comparison with a grinding process, the proposed method claims a higher efficiency and time saving. Results from X-ray diffraction have indicated that no appreciable changes, in the alpha Al(2)O(3) phase used as the raw material, have occurred. The effects of the experimental conditions such as the heat treatment time and the AlCl(3)/Al(2)O(3) weight ratio have been investigated and results have shown that the AlCl(3)/Al(2)O(3) weight ratio has an important influence on the size reduction efficiency of the method.

Keywords: grinding; alumina powder; localized etching; size reduction