Effect of Zn/Si ratio on structural and dielectric properties of ZnO-Al2O3-B2O3-SiO2 glass-ceramics

As communication technologies advance toward high frequency bands, demand for low-temperature co-fired ceramic (LTCC) materials with low dielectric constants ( ε r ) and high quality factors ( Q×f ) continues to surge. In this work, ZnO-Al 2 O 3 -B 2 O 3 -SiO 2 (ZABS) glass-ceramics were prepared using water-quenching followed by solid-state sintering. The effect of Zn/Si ratio on crystallization activation energy, sintering behavior, phase evolution, microstructure, and dielectric properties of glass-ceramics were researched. Results indicated that the crystallization tendency of glass-ceramics reduces with the Zn/Si ratio decreases from 2 to 1.38 because of the enhances glass network stability resulting from increases SiO 2 content. However, a further decrease in the Zn/Si ratio leads to intensified crystallization tendency, which is caused by the occurrence of phase separation in the glass. All samples achieve densification in the range of 875–925 °C, with Zn 2 SiO 4 as the main crystalline phase. Dielectric properties are significantly improved by decreasing the ZnO content and increasing the SiO 2 content. The glass-ceramics with Zn/Si = 1.38 sintered at 875 °C/2 h exhibits excellent performance: ε r  = 5.3, Q×f  = 28200 GHz (at 15.73 GHz), a temperature coefficient of resonant frequency ( τ f ) of −33 ppm/°C, and a flexural strength of 119 MPa. These excellent dielectric properties make the developed glass-ceramics promising candidates for future LTCC applications.