Dielectric properties of low-temperature sintered NaBi(WO₄)₂ ceramics

A novel NaBi(WO4)(2), (NBW) cerarnic prepared by solid-phase synthesis, the phase structure, morphology, sintering properties, and microwave dielectric properties of NBW ceramic were investigated. NBW is a chemical properties stable compound and was used without special packaging. The NBW ceramic can be sintered densification at temperatures from 625 to 800 degrees C for 1-4 h. The X-ray diffraction showed that the NBW ceramic sintered at temperatures from 625 to 800 degrees C for 2 h is a tetragonal crystal scheelite structure single-phase ceramic. With the increase of sintered lemperature, the permittivity and quality factor (Qf value) first :increased then decreased, while the temperature coefficient of resonant frequency gradually decreased. The dielectric properties of NBW ceramic sintered at 650 degrees C for 2 h were permittivity of 14.36, Qf of 16 503 GHz, and temperature coefficient of resonant frequency of -1.055 x10(-5) degrees C-1. When NBW was co-fired with Ag, it reacted with Ag to form Ag2W2O7, but NBW had chemical compatibility with Au and Al.