Effect of ZrO 2 addition on MgAl 2 O 4 spinel from commercial grade oxide reactants

Abstract Dense stoichiometric magnesium aluminate spinel was developed from commercially available fused magnesia and sintered alumina sources by solid oxide reaction in a single firing. Mixed oxide compositions were compacted under a uniaxial pressure of 150 MPa and then fired in the temperature range of 1200–1600 °C. Effect of addition of ZrO 2 up to 2 wt% was also studied. The dilatometric study was done to study the spinel formation with varying amount of ZrO 2 . Sintered products were characterized for densification and phase analysis study. 1600 °C sintered products were also characterized for bending strength and thermal shock resistance properties. Microstructural study with EDAX was also done to understand the grain development on sintering in the compositions and effect of zirconia in the sintered products. ZrO 2 was found to enhance the spinel formation reaction and densification of spinel. Dense compact microstructure was observed with increased strength values for compositions containing ZrO 2 . Also, ZrO 2 containing compositions showed much higher retained strength values till 6 thermal cycles after thermal shock.