Thermal properties and crystallization of lithium-mica glass and glass-ceramics

The purpose of this study was the synthesis of two groups of Li-mica glass-ceramics denoted by lepidolite (Al2.5F2KLi1.5O10Si3) and Li-phlogopite (LiMg3AlSi3O10F2). The studied system was SiO2-Al2O3-MgO-K2O-Li2O. A total of 3 compositions were prepared. Bulk casted glasses and sintered glass-ceramics of Li-phlogopite and lepidolite systems, were prepared. Eucryptite and virgilite were two prior phases of lepidolite and Li-phlogopite crystallization. It was shown that the obtained glass-ceramics have lower TEC than corresponding glasses. Sinterability of lepidolite glass-ceramic was shown that improved by increasing the Al2O3 content in glass composition. TEC and microhardness values were alpha = 6.08 x 10(-6)/degrees C, 755 +/- 11.1, alpha = 7.86 x 10(-6)/degrees C, 739 +/- 7.4 and alpha = 5.05 x 10(-6)/degrees C, 658 +/- 6.2 H/V for Li-lep, Klep1 and Klep2 glasses, respectively. (C) 2013 Elsevier B.V. All rights reserved.