Ultra-low temperature co-fired ceramics with adjustable microwave dielectric properties in the Na 2 O–Bi 2 O 3 –MoO 3 ternary system: a comprehensive study

• Published in: Journal of materials chemistry. C, Materials for optical and electronic devices Vol. 10; no. 6; pp. 2008 - 2016
• Main Authors: Hao, Shu-Zhao, Zhou, Di, Pang, Li-Xia, Dang, Ming-Zhao, Sun, Shi-Kuan, Zhou, Tao, Trukhanov, Sergei, Trukhanov, Alex, Sombra, Antonio Sergio Bezerra, Li, Qiang, Zhang, Xiu-Qun, Xia, Song, Darwish, Moustafa A.
• Format: Journal Article
• Language: English
• Published: 10.02.2022
• ISSN: 2050-7526; 2050-7534
• DOI: 10.1039/D1TC05557G

Herein, a series of microwave dielectric materials in the Na 2 O–Bi 2 O 3 –MoO 3 ternary system, such as Na 2 MoO 4 , Na 6 Mo 10 O 33 , Na 2 Mo 2 O 7 , Bi 2 Mo 3 O 12 , Bi 2 Mo 2 O 9 , and Bi2MoO6, were studied via phase identification, microstructure characterization, spectral analysis and microwave dielectric property tests; all the samples of each component could be sintered below 750 °C. Three different kinds of bulk ceramics, x (NaBi) 0.5 MoO 4 –(1− x )Na 2 MoO 4 ( x = 0.2–0.6), x (NaBi) 0.5 MoO 4 –(1− x )Bi 2 MoO 6 ( x = 0.6, 0.8) and 0.5(NaBi) 0.5 MoO 4 –0.5Bi 2 Mo 2 O 9 , were considered as the main research objects in this work. The sintering temperature of the x (NaBi) 0.5 MoO 4 –(1− x )Na 2 MoO 4 ( x = 0.2–0.6) composite ceramics ranged from 600 °C to 640 °C; high-performance microwave dielectric properties with relative permittivities in the range of 8.9–16.2, Q f (quality factor) values in the range of 11 050 GHz–8,900 GHz, and τ f values ranging from −27–11 ppm °C −1 could be obtained in these ceramics. For the x (NaBi) 0.5 MoO 4 –(1− x )Bi 2 MoO 6 ( x = 0.6, 0.8) composite ceramics, a near-zero τ f value (−2.6 ppm °C −1 ) was achieved with the 0.8(NaBi) 0.5 MoO 4 –0. 2 Bi 2 MoO 6 ceramic sintered at 720 °C with a middle-permittivity of 32.6 and a Q f value of 14570 GHz. The multiphase ceramic 0.5(NaBi) 0.5 MoO 4 –0.5Bi 2 Mo 2 O 9 could be sintered at 680 °C; the dense sample had a relative permittivity of 35.7, a Q f value of 9780 GHz and a small positive τ f value of 17 ppm °C −1 . As this study shows, the Na 2 O–Bi 2 O 3 –MoO 3 ternary system had a lot of new composite ceramics with low sintering temperatures and great microwave dielectric properties. All these materials could be regarded as candidates applicable to LTCC/ULTCC technology.