Non-isothermal crystallization kinetics and properties of low temperature co-fired LiAlSi3O8-based glass-ceramics using zirconia additive

Some LiAlSi3O8-based glass-ceramics with various contents of zirconia additions (0-4 wt%) were synthesized via solid state reaction. The influences of zirconia content on the microstructure, bulk densities, phase composition, coefficient of thermal expansion, bending strength and dielectric properties of the samples were discussed. The two crystals of LiAlSi3O8 and MgSiO3 can be found in all the samples, and the third phase of ZrSiO4 was identified only in the samples with zirconia content of 2 wt% and 4 wt%. In addition, the zirconia addition is beneficial to the sintering densification, as well as the improvement of bending strength and dielectric properties. The theoretical coefficient of thermal expansion of glass-ceramics calculated by a unique model was close to the experimental data. This shows that the model is helpful to predict the coefficient of thermal expansion of the LiAlSi3O8-based glass-ceramics. Crystallization kinetics of the LiAlSi3O8-based glass-ceramics was studied in the framework of the Kissinger, Ozawa and Augis-Bennett models. And the activation energy and Avrami index were determined by using differential scanning calorimetry. The results showed that the increase of zirconia content reduced the activation energy and changed the crystallization mechanism. The sample with 4 wt% zirconia sintered at 875 degrees C exhibited excellent properties, indicating that it is a potential candidate for low temperature substrate materials.