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0966-T10-06

Effect of CuO on Microstructure and Microwave Dielectric Properties of CaTiO3-Ca(Zn1/3Nb2/3)O3 Ceramics System Hongtao Yu1, Hua Hao1, Hanxing Liu1, and Zhongqing Tian2 1 State Key Laboratory of Advanced Technology for Materials Synthesis and Processing, Wuhan University of Technology, Wuhan, 430070, China, People's Republic of 2 Chongqing Institute of Technology, Chongqing, 400050, China, People's Republic of

ABSTRACT The microstructure and microwave dielectric properties of the CuO-doping CaTiO3-Ca(Zn1/3Nb2/3)O3 ceramics prepared by the conventional solid-method were investigated. XRD results indicate the ceramics with orthorhombic pervoskite structure are single phase for all CuO additives. And CuO-doping decreases the sintering temperature and enhances the microstructures, effectively. Thus, CuO-doping can effectively promote the microwave dielectric properties. At the level of 1.0wt% CuO additive, the quality factor increases from 10860 to 13900GHz and any significant changes are not observed in the dielectric constant and the temperature coefficient of frequency. 1. INTRODCTION The rapid popularization of microwave communications has stirred up downsizing the devices for convenience of use. These microwave dielectric ceramics must combine a high relative permittivity (K>25) with a low dielectric loss which means a high quality factor (Qf >5000GHz) and a near zero temperature coefficient of resonant frequency (TCF≈0ppm/∫C). In order to miniaturization of devices, multilayer structures with low sintering temperatures are needed to co-fire with low melting temperature conductors. In the recently ten years, the effort has been concentrated upon the fabrication of a small resonator within the multi-layer integrated circuit. In addition, the sintering temperatures of conventional microwave dielectric ceramics used as dielectric resonators, filters, and other communication devices are normally 1400~1600∞C, such as Ba(Mg1/3Ta2/3)O3, (Zr,Sn)TiO4.[1.2] Generally, for these microwave dielectric ceramics the sintering temperatures are too high to co-fire with the low melting point metal electrodes such as silver or cooper. Low melting glass additive, chemical processing, and small particle sizes of the starting materials are generally advantageous to reduce the sintering temperature of dielectric materials.[3-5] In previous researches, liquid phase fluxes such as B2O3, CuO, V2O5 and Bi2O3 were introduced as sintering aids to low the sintering temperature of ceramics and obtain good dielectric properties. [3, 6-8] In our previous research works, 0.3CaTiO3-0.7Ca(Zn1/3Nb2/3)O3 ceramics are found to exhibit a good microwave dielectric properties of a high permittivity (K~51), a good quality factor (Qf ~10860GHz) and a near zero temperature coefficient of resonant frequency (TCF ~ -6 ppm/∫C) in the (1-x)CaTiO3-xCa(Zn1/3Nb2/3)O3 system. But the sintering temperature of the

sample ceramics is about 1350~1400∫C [9]. It is well known that the dielectric loss of systems depends on not only the vibration of crystal la