Publication Date:
2012-02-08
Description:
To improve the microwave dielectric properties, CuO was doped into composite ceramics BaTi 4 O 9 – BaZn 2 Ti 4 O 11 by the solid-state reaction. CuO worked as flux former and caused the liquid-phase sintering mechanism, which effectively improved the densification process and lowered the sintering temperature by nearly 100°C. Moreover, Cu 2+ substituted for Zn 2+ sites in BaZn 2 Ti 4 O 11 phase, which led to the increase of BaZn 2 Ti 4 O 11 phase and the reduction of lattice parameters of BaZn 2 Ti 4 O 11 phase, and both these two results had the positive effect on the dielectric properties, especially the Q × f value. As increasing CuO content from 0.0 to 3.0 wt%, the dielectric constant ( ε r ) increased from 35.5 to 36.5, the Q × f value increased first from 49 100 GHz to the peak value 62 600 GHz (1.0 wt% CuO ) and thereafter decreased to 31 900 GHz, and the temperature coefficient of resonant frequency ( τ f ) kept in a low value as 〈2.0 wt% CuO was added. At last, 0.85 BaTi 4 O 9 –0.15 BaZn 2 Ti 4 O 11 ceramics with 1.0 wt% CuO sintered at 1150°C for 3 h showed excellent microwave dielectric properties: the high ε r = 36.4, the high Q × f = 62 600 GHz and the near-zero τ f = +0.2 ppm/°C.
Print ISSN:
0002-7820
Electronic ISSN:
1551-2916
Topics:
Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
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