关键词: 电熔合成法;镁铝尖晶石;二氧化钛;固溶体

Abstract: Caustic burned magnesia powder and industrial alumina were used as raw materials for the fused synthesis of magnesium aluminate (MA)spinel materials,the effect of titania as the additive on their phase composition and microstructure was investigated. The phase composition,cell parameters and fracture morphology of the samples were analyzed by XRD and SEM. The results show that:addition of titania increases the unit cell parameter and bulk density of the MA spinel,further,the sintering performance is improved. In addition,the cell parameters and volume of MA spinel show the tendency of firstly increased and then decreased with the increase of titania content. As the titanium dioxide and magnesium titanate are dissolved in magnesia alumina spinel,the cell parameters and volume of the unit are increased,however,the anexcess amount of magnesium titanate at the grain boundaries hinderes its growth,which results in the decrease of the cell parameters and the unit cell volume. In the process of preparation of fused spinel,the amount of titanium dioxide should not exceed 5wt%.

Key words: fused synthesis;magnesia alumina spinel;titanium dioxide;solid solution