Abstract

The effects of different milling methods applied during production of a 99,7 % alumina quality from a commercial Bayer alumina powder were studied in an interlaboratory test. Grinding and doping of the powder with MgO was carried out by stirred ball or vibration ball milling, with different milling media and linings of the mills. The powder batches were consolidated by pressing, sintering and post HIPing. The materials were characterized in different stages of the production process in order to analyze the role of contamination by wear debris and of the granulometry on microstructure and mechanical properties of the final products. It could be shown, that a satisfying agreement in the results of different laboratories was achieved for common characterization methods. The sensitivity of the applied methods turned out to be sufficient to detect differences in contamination and granulometry, which lead to significant variations in microstructure and properties of the final products.