Low-temperature firing, temperature-independent, and microwave dielectric performances of ZnNb1.8V0.1O5.75 systems for LTCC applications.

The effects of TiO 2 doping on the phase transition and microwave dielectric performances of ZnNb 1.8 V 0.1 O 5.75 @xTiO 2 (0.05 ≤ x ≤ 0.60) ceramics prepared by conventional mixing methods were investigated. In this study, we report for the first time the phase transition of ZnNb 2 O 6 with columbite structure at low temperature (950 °C) where the τ f value is adjusted to near zero. With the increase of TiO 2 doping, the following phase transitions are experienced in the ceramics: columbite + monoclinic → columbite + monoclinic + ixiolite → monoclinic + ixiolite → monoclinic + ixiolite + rutile. The microscopic morphology of ceramics is greatly influenced by TiO 2 doping. The grain size of ceramics continues to grow as TiO 2 doping increases. The microwave dielectric performances of ceramics are intimately connected to the phase transition process, which occurs when the Q × f value constantly declines while the τ f value steadily increases and is adjusted to near zero at x = 0.50. After sintering at 950 °C for 6 h, the most optimal microwave dielectric performances were obtained for x = 0.50 with a dielectric constant of 41.18, a Q × f value of 6852 GHz, and a τ f value of +6.83 ppm/°C, providing a new option with great potential for microwave devices requiring medium dielectric ceramics. [ABSTRACT FROM AUTHOR]