Some studies on nucleation, crystallization and microstructural behaviour of mica glass-ceramics in the system 0.8BaO.0.2K2O.4MgO.AI2O 3.6SiO2.2MgF2

Ceramic Engineering Division, Department of Chemical Technology, University of Calcutta, 92, Acharya Prafulla Chandra Road, Kolkata-700 009, India E-mail : prabir.maiti@gmail.com Fax : 91-33-23519755 Govt. College of Engineering and Ceramic Technology, 73, A. C. Banerjee Lane, Kolkata-700 010, India Manuscript received 28 September 2010, accepted 25 February 2011 Glass-ceramics containing barium fluorophlogopite as a main crystal phase based on the system 0.8BaO. 0.2K2O.4MgO.Al2O3.6SiO2.2MgF2 was investigated with respect to phase separation, nucleation and crystallization by Differential thermal analysis (DTA), X-ray diffraction (XRD) and Scanning electron microscopy (SEM). The glass transition temperature (Tg) and two distinct crystallization peak temperatures were observed in DTA curve. The crystallization kinetics of glass-ceramics wa• also studied. Avrami exponent and activation energy for the first peak crystallization temperature (Tp1) were 2.7 and 226.3 ± 3 kJ/mol and the corresponding values for second peak crystallization temperature (Tp2) were 3.7 and 322.6 ± 3 kJ/mol