Fabrication and properties of Li2O-Al2O3-SiO2 glass/Al2O3 composites for low temperature co-fired ceramic applications

The Al2O3 filler was added to a Li2O-Al2O3-SiO2 glass-ceramic in order to increasing the bending strength and coefficient of thermal expansion of these composites for low temperature co-fired ceramic applications. The influence of the Al2O3 filler on the sintering, microstructure and characteristics was investigated. When the content of Al2O3 increases from 0 to 20 wt%, the bending strength increases from 104 to 155 MPa and the coefficient of thermal expansion increases from 1.26 to 2.65 ppm/degrees C. The Al2O3 filler also plays an important role for obtaining desired sintering, microstructure and dielectric properties. But the linear shrinkage, microstructure, mechanical and dielectric properties would deteriorate because of the excessive Al2O3 and the decrease of glass content. The composite with 20 wt% Al2O3 filler exhibits excellent properties: a low sintering temperature of 800 degrees C, a good density of 2.78 g/cm(3), a dense microstructure, an high bending strength of 155 MPa, good dielectric properties (epsilon(r): 8.0 and tan delta: 2.4 x 10(-3)) and a low CTE of 2.65 ppm/degrees C.