Synthesis and microwave dielectric properties of Bi2Ge3O9 ceramics for application as advanced ceramic substrate. Issue 2 (February 2017)

• Record Type: Journal Article
• Authors: Ma, Xing-Hua; Kweon, Sang-Hyo; Nahm, Sahn; Kang, Chong-Yun; Yoon, Seok-Jin; Kim, Young-Sik
• Is Part Of: Journal of the European Ceramic Society. Volume 37:Issue 2(2017)
• Page Start: 605
• Page End: 610
• Publication Date: 2017-02
• Subjects: Bi2Ge3O9 ceramics -- LTCC -- Microwave dielectric properties -- Advanced ceramic substrates; Ceramic materials -- Periodicals; Composite materials -- Periodicals; Matériaux céramiques -- Périodiques; Composites -- Périodiques; Ceramic materials; Composite materials; Periodicals; Electronic journals; 666.05
• DOI: 10.1016/j.jeurceramsoc.2016.08.037
• Languages: English
• ISSNs: 0955-2219

Abstract

Abstract: During the synthesis of Bi2 Ge3 O9 ceramics using Bi2 O3 + 3GeO2 powders, the Bi4 Ge3 O12 phase was formed at low temperature (≤800 °C). Bi4 Ge3 O12 preferentially adopted GeO2 -excess phase, and this phase was consistently present in the sintered Bi2 Ge3 O9 ceramic as a secondary phase. Therefore, Bi4 Ge3 O12 powder was first calcined and subsequently reacted with GeO2 powder to obtain the pure Bi2 Ge3 O9 ceramic through the following reaction: 1/2Bi4 Ge3 O12 + 3/2GeO2 → Bi2 Ge3 O9 . Formation of the Bi2 Ge3 O9 phase was initiated at temperature of 850 °C. The pure Bi2 Ge3 O9 ceramic sintered at 875 °C for 8 h had a dense microstructure with an average grain size of 2.7 μm. Furthermore, the pure Bi2 Ge3 O9 ceramic exhibited promising microwave dielectric properties for the advanced ceramic substrate: εr = 9.7, Q × f = 48, 573 GHz and τf = −29.5 ppm/°C.