Microwave Dielectric Properties of xMgO-(1-x)B2O3 Ceramics

作者：Kan Akinori^*; Ogawa Hirotaka; Sumino Makoto; Nishizuka Makio; Suzuki Eri

来源：Japanese Journal of Applied Physics, 2009, 48(9): 09KE03.

DOI：10.1143/JJAP.48.09KE03

The effects of B2O3 doping on the microwave dielectric properties of a MgO compound were characterized in this study. The MgO and Mg3B2O6 compounds were recognized in the XRPD profiles of xMgO-(1-x)B2O3 ceramics at a sintering temperature of 1350 degrees C for 4 h in a covered crucible. From the calculation of weight fraction of the compounds, the slight deviation in the concentrations of B2O3 and MgO from the stoichiometric composition of xMgO-(1-x)B2O3 ceramics was also observed, and was attributed to the vaporization Of B2O3 and the decomposition Of Mg3B2O6 compound during the sintering. In the composition range of 0.95-0.99, abnormal grain growth of xMgO-(1-x)B2O3 ceramics was observed; therefore, the decomposition of Mg3B2O6 compound into liquid phase and MgO compound may play an important role in enhancing the grain growth of the ceramics. The dielectric constant of xMgO-(1-x)B2O3 ceramics ranged from 6.9 to 9.4 depending on the amount of Mg3B2O6 and MgO compounds, whereas the remarkable variation in the Q.f value of the ceramics was observed at x > 0.95. As a result, a maximum Q.f value of approximately 773000 GHz was obtained at x = 0.99. Such the variation in the Q.f value may be attributed to the sinterability of MgO compound, which is related to microstructural changes in the ceramics.

• 出版日期2009-9