Microstructure and microwave dielectric characteristics of (1−x)Ba(Zn1/3Ta2/3)O3–xBaTi4O9 ceramics

(1 - x)Ba(Zn{sub 1/3}Ta{sub 2/3})O{sub 3}-xBaTi{sub 4}O{sub 9} (0.1 {<=} x {<=} 0.85) composites are prepared by mixing 1150 deg. C-calcined BaTi{sub 4}O{sub 9} with 1150 deg. C-calcined Ba(Zn{sub 1/3}Ta{sub 2/3})O{sub 3} powders. The crystal structure, microwave dielectric properties and sinterabilites of the (1 - x)Ba(Zn{sub 1/3}Ta{sub 2/3})O{sub 3}-xBaTi{sub 4}O{sub 9} ceramics have been investigated. X-ray diffraction patterns reveal that BaTi{sub 4}O{sub 9}, ordered and disordered Ba(Zn{sub 1/3}Ta{sub 2/3})O{sub 3} phases exist independently over the whole compositional range. The sintering temperatures of (1 - x)Ba(Zn{sub 1/3}Ta{sub 2/3})O{sub 3}-xBaTi{sub 4}O{sub 9} ceramics are about 1240 - 1320 deg. C and obviously lower than those of Ba(Zn{sub 1/3}Ta{sub 2/3})O{sub 3} ceramics. The dielectric constants ({epsilon}{sub r}) and the temperature coefficient of resonant frequency ({tau}{sub f}) of (1 - x)Ba(Zn{sub 1/3}Ta{sub 2/3})O{sub 3}-xBaTi{sub 4}O{sub 9} ceramics increase with the increase of BaTi{sub 4}O{sub 9} content. Nevertheless, the bulk densities and the quality values (Q x f) of (1 - x)Ba(Zn{sub 1/3}Ta{sub 2/3})O{sub 3}-xBaTi{sub 4}O{sub 9} ceramics increase with the increase of Ba(Zn{sub 1/3}Ta{sub 2/3})O{sub 3} content. The results are attributed to the higher density and quality value of Ba(Zn{sub 1/3}Ta{sub 2/3})O{sub 3} ceramics, the better grain growth, and the densification of sintered specimensmore » added a small BaTi{sub 4}O{sub 9} content. The (1 - x)Ba(Zn{sub 1/3}Ta{sub 2/3})O{sub 3}-xBaTi{sub 4}O{sub 9} ceramic with x = 0.1 sintered at 1320 deg. C exhibits a {epsilon}{sub r} value of 31.5, a maximum Q x f value of 68500 GHz and a minimum {tau}{sub f} value of 4.1 ppm/deg. C.« less