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Willemite (Zn₂SiO₄); forsterite (Mg₂SiO₄); microwave ceramics; dielectric property; microstructure; millimetre-wave frequency.

(ZnMg)₂SiO₄ powders was prepared by the sol–gel process, and the microstructure and dielectric properties of (Zn_1–𝑥Mg_𝑥)₂SiO₄ microwave materials were investigated systematically. TG-DSC and XRD analyzes for gels indicate that the (ZnMg)₂SiO₄ with pure willemite phase could be obtained at low temperature of 850°C. Further, XRD illustrates that just small amounts of Mg can be incorporated into Zn₂SiO₄ lattice, and the solid solution limit of Mg in Zn₂SiO₄ is about 𝑥 = 0.1. By appropriate Mg substitution for Zn, the sintering range is widened and the sintering temperature of Zn₂SiO₄ ceramics can be lowered effectively. SEM shows that Mg-substitution for Zn can promote the grain growth of Zn₂SiO₄. Moreover, the microwave dielectric properties strongly depended on the substitution content of Mg and sintering temperatures. (Zn_0.8Mg_0.2)₂SiO₄ dielectrics sintered at 1170°C show the condense microstructure with small uniform grains and best microwave properties: 𝜀_r = 6.3, 𝑄 × 𝑓 = 189800 GHz and 𝜏_f = –63 ppm/°C.

Bo Li¹ Ying Yuan¹ Shuren Zhang¹ Hongmei Jiang¹

1. State Key Laboratory of Electronic Thin Films and Integrated Devices, University of Electronic Science and Technology of China, Chengdu 610054, P.R. China

Published

July 2011

Manuscript received

6 January 2010

Manuscript revised

26 February 2010