Dielectric Properties and Crystal Structure of Mg4Nb2O9 Ceramics with Mg2+ Substituted by Zn2+ and Co2+

スポンサーリンク

概要

• 論文の詳細を見る

• Dielectric properties of (Mg0.9Zn0.1)4-xCoxNb2O9 prepared by solid state reaction were investigated. The theoretical polarizability of (Mg0.9Zn0.1)4-xNb2O9--xCoNb2O9 increased with Co substitution, x. Single-phase perovskite can be obtained in the range from x=0.3 to 1. The maximum properties of the (Mg0.9Zn0.1)4-xCoxNb2O9 system were namely, an obtained \varepsilon_{\text{r}} value of 12.78, a Q\times f value of 190000GH, and a \tau_{\text{f}} value of -65 ppm/°C for (Mg0.9Zn0.1)4-xCoxNb2O9 in x=0.3 ceramics sintered at 1200 °C. The theoretical polarizability of (Mg0.9Zn0.1)4-xNb2O9--xCoNb2O9 increased with Co substitution, x. Mg4Nb2O9 with Mg2+ substituted by Zn2+ and Co2+ not only improved the microwave dielectric properties, but also decreased sintering temperature. From the calculation of the covalency of cation--oxygen bonds, it is found that the covalency of the Co--O bond is lower than that of the Mg--O bond and the difference in the covalency between these cation--oxygen bonds influences the temperature dependence of dielectric constant on the compounds. As for the dielectric constant (\varepsilon_{\text{r}}) and the quality factor (Q\times f) of the ceramics, these values ranged from 11.55 to 14.48 and from 190,000 to 4,700 GHz, respectively, depending on the composition x. The maximum properties of the (Mg0.9Zn0.1)4-xCoxNb2O9 system, namely, a dielectric constant of 12.78, a Q\times f value of 190,000 GHz and a \tau_{\text{f}} value of -65 ppm/°C were obtained for (Mg0.9Zn0.1)4-xCoxNb2O9 (x=0.3) ceramics sintered at 1200 °C.

• 2012-08-25

著者

• Chen Yuan-bin

  Department Of Electrical Engineering National Cheng Kung University

• Chen Yuan-Bin

  Department of Engineering and Management of Advanced Technology, Chang Jung Christian University, Tainan 71101, Taiwan

関連論文

• New Dielectric Material System of La(Mg_Ti_)O_3-CaTiO_3 at Microwave Frequencies
• Microwave Dielectric Properties and Microstructure of 0.85MgTiO_3-0.15Ca_La_TiO_3 Dielectric Ceramics with Added Sintering Aids
• Microwave Dielectric Properties and Microstructure of 0.85MgTiO3–0.15Ca0.6La0.8/3TiO3 Dielectric Ceramics with Added Sintering Aids
• Observation on Wind Turbulence Characteristics of Short Term Period at the Northeastern Coast of Taiwan
• Microwave Dielectric Properties and Microstructures of 0.5La(Mg1/2Ti1/2)O3–0.5CaTiO3 Ceramics with B2O3 Addition
• Dielectric Properties and Crystal Structure of Mg4Nb2O9 Ceramics with Mg2+ Substituted by Zn2+ and Co2+
• Effect of RF Power on Physical Properties of MgTiO3 Films by RF Magnetron Sputtering

スポンサーリンク