Low loss dielectrics based on two borate glasses, (13-19)CaO·(13-19) La2O3·68B2O3 and (13-19)ZnO·(13-19)La2O3·68B 2O3, have been investigated with a focus on effects of the CaO/La2O3 and ZnO/La2O3 ratios on physical and dielectric properties. All samples were prepared by mixing glass with 40 wt% Al2O3 filler and by firing at 850 °C for 30 min. The effects of increasing relative contents of Ca and Zn were found to be opposite specifically in microstructure evolution and crystallization behavior, and thus, dielectric properties. For example, the 13CaO· 19La2O3·B2O3 sample having the lowest Ca content showed the highest Q × f of ∼8100, while the 19ZnO·13La2O3·B2O3 sample having the highest Zn content showed the highest Q × f of ∼18,100. The extensive crystallization of low loss phases, i.e., LaBO 3 and LaAl2.03(B4O10)O 0.54, as well as the improved level of densification are assumed to be responsible for better dielectric performance.
All Science Journal Classification (ASJC) codes
- Mechanical Engineering
- Mechanics of Materials
- Materials Chemistry
- Metals and Alloys