A novel approach to synthesis of nanosize MgAl_2O_4 spinel powder through sol-gel citrate technique and subsequent heat treatment

摘要

This paper summarizes a study on the influence of heat-treatment atmosphere in synthesis of nanosize MgAl_2O_4 spinel powder employing sol-gel citrate route. Based on measurement of BET specific surface area, crystallite size, simultaneous thermal analysis, and microscopic observation, it was clarified that the argon atmosphere used for heat treatment of precursor reduced the particle size of synthesized ceramic powder significantly. Comparing with heat treatment in air atmosphere, it was elucidated that the carbonaceous material remaining from citrates has an important role in hindering the particle sintering. Also the slower heat generation in argon atmosphere creates a chance to achieve a nanocrystalline MgAl_2o_4 spinel powder with crystallite size in the range of 5-7 nm. The present novel approach shows that the argon treatment confronts the problem of sudden heat generation in sol-gel citrate method to synthesize nanosize MgAl_2O_4 spinel particles in the range of 20-100 nm.