Effect of CaO content on structure and properties of low temperature co-fired glass-ceramic in the Li2O-Al2O3-SiO2 system

Glass-ceramics based on the Li2O-Al2O3-SiO2 system were synthesized by the conventional melt-quenching technology. The glass-ceramics were designed based on silicon oxide replacement with simultaneous increasing calcium oxide. The effects of CaO on the microstructure, densification, thermal, dielectric and mechanical properties of the glass-ceramics were investigated. This glass-ceramic has a low softening point and could be sintered at a low temperature of 800 degrees C. The addition of CaO promotes the formation of the CaMgSi2O6 phase and could improve the microstructure, densification and mechanical property. The coefficient of thermal expansion of the glass-ceramic increases with the content of CaO and could match that of silicon chips. The sample LAS2 (2.1 wt% CaO) sintered at 800 degrees C for 0.5 h exhibits excellent properties: high density of 2.48 g/cm(3), low dielectric constant of 6.8 and loss of 3.7 x 10(-3), high three point bending strength of 154 MPa, and low CTE value of 1.9 x 10(-6)/degrees C.