Sintering behavior and mechanical properties of mica-diopside glass-ceramic composites reinforced by nano and micro-sized zirconia particles

Primary glass-ceramic containing phlogopite and diopside crystals were prepared through sintering of 70 wt.% mica bearing and 30 wt.% wollastonite bearing base glasses. Different amounts of microsized and nanosized partially stabilized zirconia particles were added to the aforementioned primary composition to improve mechanical properties. Glass-ceramics and the relevant composites were sintered in a temperature interval of 950-1020 degrees C at the heating rate of 10 degrees C/min and soaking time of 3 hat maximum temperature. According to the obtained results, phlogopite and diopside were formed as the main crystalline phases during sintering of zirconia free specimens. However, dissolution of zirconia in the glass matrix led to the formation of the zircon phase in zirconia containing specimens. Based on the SEM observations, residual nano-sized zirconia was detectable as the agglomerates in the microstructures. Micro-sized zirconia enhanced bending strength of the relevant composites. On the other hand, toughness was promoted in the presence of nano-sized zirconia particles. (C) 2012 Elsevier B.V. All rights reserved.