Abstract: BaAl2-2xZn2xSi2O8(x = 0, 0.25%, 0.5%, 0.75%, 1%, 1.5%) ceramics were synthesized by solid state sintering method. The effects of Zn2+ dopant concentration on the crystal structure and dielectric properties of BaAl2Si2O8 (BAS) microwave dielectric ceramics were investigated. The results show that the O2- vacancies, due to Zn2+ substitution of Al3+, can effectively promote the transformation of BAS from hexagonal to monoclinic phase, which reduces the sintering temperature to 1350 ℃ and improves
parameters such as the density, quality factor (Q×f) and temperature coefficient of resonant frequency ( τf ). BAS ceramics with optimized dielectric properties can be obtained when x=0.75% and sintering temperature is 1350 ℃. The optimized dielectric parameters are εr=6.67, Q×f=46226 GHz, τf= -25.21×10-6/ ℃.
Key words: BaAl2Si2O8 ; oxygen vacancies; monoclinic phase; crystal structure; dielectric properties