Systematic studies on crystallization, microstructure and mechanical behavior of barium doped potassium mica glass

Department of Chemistry, Siliguri College, University of North Bengal, Siliguri-734 001, Darjeeling, West Bengal, India Department of Chemistry, St. Paul’s Cathedral Mission College, 33/1, Raja Rammohan Roy Sarani, Kolkata-700 009, India E-mail : palbiswajit@yahoo.com Manuscript received 07 February 2017, accepted 04 May 2017 A barium doped glass-ceramics with the composition of 0.4BaO·0.6K2O·4MgO·Al2O3 ·6SiO2 ·2MgF2 was prepared. Two crystallization peaks in DTA ascertain that the first one arises for the formation of Kfluorophlogopite while the second peak is for Ba-fluorophlogopite. The activation energy for the first and second crystallization temperatures are 279.2 and 326.4 kJ/mol. The decrease in hardness value with increase in machinability at intermediate temperature range is due to the formation of either potassium and/or barium fluorophlogopites phases. An interconnected ‘house of cards’ microstructure is developed at higher temperature region. The crystal phases like enstatite and hexa celsian, etc. are formed beyond 1100 oC