Effect of CaO content on structure and properties of low temperature co-fired glass-ceramic in the Li_2O-Al_2O_3-SiO_2 system

摘要

Glass-ceramics based on the Li_2O-Al_2O_3-SiO_2 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 ℃. The addition of CaO promotes the formation of the CaMgSi_2O_6 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 ℃ 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 × 10~(-3), high three point bending strength of 154 MPa, and low CTE value of 1.9 × 10~(-6)/℃.