MULLITE FROM HIGH TEMPERATURE CHEMICAL REACTION METHOD  EVALUATION OF STOICHIOMETRIC Al2O3/SiO2 RATIO, PHASE COMPOSITION AND MICROSTRUCTURE

E. Tkaczewska

Volume : IV, Issue : VI, June - 2015

MULLITE FROM HIGH TEMPERATURE CHEMICAL REACTION METHOD EVALUATION OF STOICHIOMETRIC Al2O3/SiO2 RATIO, PHASE COMPOSITION AND MICROSTRUCTURE

E. Tkaczewska

Abstract :

Paper evaluates properties and microstructure of mullite prepared by high temperature solid state chemical reaction – of Al2 (SO4 ) 3 and SiO2 in molten Na2 SO4 and also of Al(OH)3 and SiO2 with/without MgO. The Al2 O3 :SiO2 molar ratio, phase composition and microstructure are discussed. The 3:2 mullite phase is formed by sintering Al(OH)3 and SiO2 at 1500 �C in presence of MgO addition. The higher content of MgO, the most advanced mullitization process. At 10wt% MgO, the highly elongated crystals of primary mullite and acicular crystals of secondary mullite are detected.