Microwave dielectric properties of two low temperature sintering ceramics in the PbO-WO3 binary system

Two microwave dielectric ceramics in the PbO-WO3 binary system, PbWO4 and Pb2WO5, with low sintering temperatures were prepared by a conventional solid-state reaction method. The Pb2WO5 ceramic could be well densified at around 520 degrees C and demonstrated high performance microwave dielectric properties with a relative permittivity similar to 16.4, a Q x f value similar to 14,805 GHz (at 7.6 GHz), and a negative temperature coefficient of resonant frequency similar to -94.5 ppm/degrees C. The PbWO4 ceramic could be well densifiecl at around 620 degrees C with a larger relative permittivity similar to 21.4, a higher Q x f value similar to 43,000 GHz (at 7.0 GHz), and a nearly zero temperature coefficient of resonant frequency similar to -7.1 ppm/degrees C. From the X-ray diffraction pattern, backscattered electron image and energy dispersive spectrometer analysis results of the co-fired samples with 20 wt% Ag or Al additive, the PbWO4 and Pb2WO5 ceramics did not react with either Ag or Al powders at their optimum sintering temperature. (C) 2015 Elsevier Ltd and Techna Group S.r.l. All fights reserved.