Low-temperature sintering of Al2O3 ceramics with high Q × f value

This study proposed a novel glass-phase sintering additive composed of ZnO, Al 2 O 3 , SiO 2 , B 2 O 3 , and Co 2 O 3 (ZASBC). Its effects on the structure and properties of Al 2 O 3 ceramics were investigated. XRD results indicated that the addition of ZASBC preserved the original hexagonal crystal system of Al 2 O 3 ceramics while reducing the optimal densification temperature to 1350 °C, achieving a bulk density of 3.972 g/cm 3 . The dielectric constant ( ε r ) reached 9.79, with its variation primarily attributed to relative density. At 1 wt% ZASBC addition, the quality factor ( Q   ×  f ) of the sample improved to 131,272 GHz. This enhancement was driven by high packing fraction and relative density. Additionally, the temperature coefficient of resonant frequency ( τ f ) was found to correlate mainly with ε r . The Al 2 Oz 3 –1 wt% ZASBC samples sintered at 1400 °C demonstrated outstanding microwave dielectric properties.