Effect of compositional variation and fineness on the densification of MgO-Al2O3 compacts

Single stage densification of magnesia-alumina compacts were studied with M gO to Al2O3 molar ratios 1:1 (stoichiometric spinel), 2:1 (magnesia rich sp inel) and 1,2 (alumina rich spinel). Attritor milling has been adopted to p roduce variation in fineness. Milling greatly improved the densification. D ensification was found to be easier for the magnesia rich composition and d ifficult for the alumina rich one. Xray diffraction patterns showed the exp ected phases in stoichiometric and magnesia rich spinel. Alumina rich compo sition showed no free corundum phase on sintering at 1650 degrees C and onl y spinel phase marks the complete solid solution of excess alumina in spine l at this composition. EDAX analysis also supports the event and also refle cts that the impurities are mainly present at the grain boundaries. (C) 199 9 Elsevier Science Ltd. All rights reserved.