NaCa4V5O17: A low-firing microwave dielectric ceramic with low permittivity and chemical compatibility with silver for LTCC applications

• Published in: Journal of the European Ceramic Society Vol. 40; no. 2; pp. 386 - 390
• Main Authors: Yin, Changzhi, Li, Chunchun, Yang, Guangjie, Fang, Liang, Yuan, Yonghai, Shu, Longlong, Khaliq, Jibran
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 01.02.2020
• Subjects: Ceramics; Dielectric properties; LTCC; NaCa4V5O17; NaCa4V5O17; Ceramics; LTCC; Dielectric properties
• ISSN: 0955-2219; 1873-619X
• DOI: 10.1016/j.jeurceramsoc.2019.09.029

Phase formation, crystal structure and dielectric properties of NaCa4V5O17 ceramics fabricated via a solid state reaction route at relatively low temperatures (780–860 °C) were investigated. NaCa4V5O17 crystallizes in a triclinic structure. Dielectric properties were measured based on the Hakki-Coleman post resonator method at microwave frequency. Specially, a specimen sintered at 840 °C demonstrated balanced dielectric properties with a permittivity εr = 9.72, a quality factor Q×f = 51,000 GHz, and a temperature coefficient of resonance frequency τf = −84 ppm/°C. NaCa4V5O17 ceramics showed excellent chemical compatibility with Ag metal electrodes. Besides, the thermal stability of resonance frequency was effectively adjusted through formation of composite ceramics between NaCa4V5O17 and TiO2 and a near-zero τf ˜ 1.3 ppm/°C accompanied with εr = 14.9 and Q×f = 19,600 GHz was achieved when 50% mol TiO2 was added. All the merits render NaCa4V5O17 a potential candidate for multilayer electronic devices.