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Abstract: K0.5(Nd1−xBix)0.5MoO4 (0.2 ≤ x ≤ 0.7) ceramics were prepared via the solid‐state reaction method. All ceramics densified below 720°C with a uniform microstructure. As x increased from 0.2 to 0.7, relative permittivity (ɛr) increased from 13.6 to 26.2 commensurate with an increase in temperature coefficient of resonant frequency (TCF) from – 31 ppm/°C to + 60 ppm/°C and a decrease in Qf value (Q = quality factor; f = resonant frequency) from 23 400 to 8620 GHz. Optimum TCF was obtained for x = 0.3 (−15 ppm/°C) and 0.4 (+4 ppm/°C) sintered at 660 and 620°C with ɛr ~15.4, Qf ~19 650 GHz, and ɛr ~17.3, Qf ~13 050 GHz, respectively. Ceramics in this novel solid solution are a candidate for ultra low temperature co‐fired ceramic (ULTCC) technology. [ABSTRACT FROM AUTHOR]

In the present work, ( Bi1− x Fe x) VO4 ( x ≤ 0.40) ceramics were prepared using the solid-state reaction method. All the ceramics could be well densified at sintering temperatures below 800°C. X-ray diffraction ( XRD) results showed that monoclinic solid solution was formed within x ≤ 0.08. When x ≥ 0.10, both monoclinic scheelite and FeVO4 phases were detected. The ( Bi0.92 Fe0.08) VO4 sample sintered at 720°C for 2 h had a permittivity of 57.5 and a Qf value of 15 000 GHz. The IR reflectivity was fitted to study the intrinsic dielectric properties, showing that the majority of the dielectric contribution for this system at microwave region was attributed to the absorptions of structural phonon oscillation in infrared region. [ABSTRACT FROM AUTHOR]

Novel glass-free low temperature firing microwave dielectric ceramics, Bi(Ga 1/3 Mo 2/3 )O 4 , with ordered scheelite structure, were prepared through a conventional solid state reaction method. Dense ceramics were prepared at sintering temperatures from 800 to 860 °C. The Bi(Ga 1/3 Mo 2/3 )O 4 compound was crystallized with B-site ordered Scheelite-type structure with space group C2/c. The Bi(Ga 1/3 Mo 2/3 )O 4 ceramics can be well sintered at about 830 °C, exhibiting good microwave dielectric properties of ε r ~26.1, Qf~49,800 GHz, and TCF~−86 ppm/°C. Intrinsic dielectric parameters of the Bi(Ga 1/3 Mo 2/3 )O 4 ceramics were estimated by fitting far-infrared (FIR) reflectance spectra with the classical harmonic oscillator model. [ABSTRACT FROM AUTHOR]