Effects of Mg/Si Ratio on Microwave Dielectric Characteristics of Forsterite Ceramics


  • N. Alford—contributing editor

  • The present work was partially supported by the National Science Foundation under grant No. 50332030, and Chinese National Key Project for Fundamental Researches under grant No. 2002 CB613302.

†Author to whom correspondence should be addressed. e-mail: kxsong3977@sina.com


Nonstoichiometric Mg2SiO4 forsterite dielectric ceramics with various Mg/Si ratios (R=2.025, 2.05, and 2.2) were prepared and characterized. The appearance of a MgSiO3 secondary phase could be effectively suppressed by adjusting the nonstoichiometry, and a single-phase forsterite structure was obtained in the present ceramics with Mg/Si ratios of 2.025 and 2.05. The microwave dielectric characteristics were significantly improved in the nonstoichiometric Mg2SiO4 ceramics on eliminating the MgSiO3 secondary phase, where an enhanced Q×f value and a suppressed temperature coefficient of resonant frequency λf were obtained. The best microwave characteristics were achieved in the nonstoichiometric forsterite ceramics with an Mg/Si ratio of 2.05: ɛr=7.5, Q×f=114 730 GHz, and λf=−59 ppm/°C.