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/°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 °C, a good density of 2.78 g/cm³, a dense microstructure, an high bending strength of 155 MPa, good dielectric properties (ε_r: 8.0 and tan δ: 2.4 × 10⁻³) and a low CTE of 2.65 ppm/°C.