Journal of Inorganic Materials ›› 2017, Vol. 32 ›› Issue (1): 91-95.doi: 10.15541/jim20160272

• Orginal Article • Previous Articles     Next Articles

Crystal Structure and Microwave Dielectric Property of Ba1-xMgxAl2Si2O8

Yao ZHANG(), Shi-Hua DING, Yang-Qiong LIU, Shao-Ying DUAN, Peng XIAO, Lin-Cai HAN   

  1. School of Materials Science and Engineering, Xihua University, Chengdu 610039, China
  • Received:2016-04-19 Revised:2016-06-08 Online:2017-01-20 Published:2016-12-15
  • Supported by:
    National Natural Science Foundtion of China (11074203);Graduate Innovation Foundation of Xihua University (ycjj2015217, ycjj2015218, ycjj2015113)

Abstract:

Barium feldspar BaO-Al2O3-SiO2 system materials have been studied extensively for application in microwave devices, microwave substrate and packaging in recent years, due to their remarkable dielectric properties. The hexacelsian-celsian transition, relationship between dielectric properties, and structure of BaO-Al2O3-SiO2 system has attracted widely academic interest. Ba1-xMgxAl2Si2O8 (x=0, 0.05, 0.1, 0.15, 0.3, 0.5) ceramics were prepared by solid state sintering processing. The crystal structure and microwave dielectric properties of BaO-Al2O3-SiO2 with different MgO contents were studied. The results show that MgO doping reduces sintering temperature and greatly promotes the transition from hexacelisian to celsian at x≥0.15, while the transition reachs 100%. MgO doping effectively increases grain size at x≤0.15. The diffraction peak of celsian is enhanced and the grain size gets larger. Moreover, the density, dielectric constant andτf of Ba1-xMgxAl2Si2O8 ceramics increases with the increase of MgO content in the range of 0.05≤x≤0.1. In addition, the resonant frequency temperature coefficient is negative. The Ba0.9Mg0.1Al2Si2O8 sintered at 1400℃ exhibits a high Q×f value of 16461 GHz, εr=6.44 and τf= -30.6×10-6 K-1 at x=0.1. The dielectric constant of Ba1-xMgxAl2Si2O8 ceramics is related with its Mg2+ polarizability and its structure. The effect of electronegativity, the size of ions and the crystal structure on Q×f value of Ba1-xMgxAl2Si2O8 ceramics are also discussed.

Key words: magnesium oxide, feldspar, celsian, crystal structure, microwave dielectric properties

CLC Number: 

  • TQ174