Synthesis and characterization of spinel precursor
- Effects of particle size in starting powder and milling -
Shiono Takeshi; Kadoyama Yoshiki; Nishida Toshihiko
Abstract:MgAl2O4 spinel precursor was synthesized from heterogeneous alkoxide solution containing MgO powder with average particle size of 0.1mm. The obtained precursor was very stable and identified as a material consisting of MgO, AlOOH and Mg4Al2(OH)143H2O. However, calcination of this precursor at 1200 deg. did not yield monolithic spinel powder. MgO from the starting material remained in the calcined powder. In order to eliminate the remaining MgO, an attempt was made to mill the precursor under various conditions by the planetary ball milling equipment. It was recognized that such milling results in the elimination of the MgO and the synthesizing the same constituents of a precursor by using MgO powder with average particle size of 0.01mm. The obtained powder was sintered at a temperature from 1300 deg. to 1600 deg. for 3h. Sintering temperature of 1500 deg. was enough to obtain polycrystalline spinel with more than 99% of theoretical density. Key Words:spinel, fine powder, alkoxide, milling, sinterability