Microstructure and microwave dielectric characteristics of ZnTi(Nb1−xSbx)2O8 ceramics

ZnTiNb2O8 is a promising new material suitable for the applications at microwave frequencies. The effects of Sb substitution on phase constitution, phase structures and properties of ZnTiNb2O8 were investigated. The unknown Columbite-type phase was determined as (Zn0.75Ti0.25)(Nb0.75Ti0.25)2O6. The Qf is closely related to the packing fraction of structure and the amount of each phase. With the decrease of packing fraction and the content of Columbite phase, the Qf decreased. The τf is related to the cation ordering of (Zn0.75Ti0.25)(Nb0.75Ti0.25)2O6 and cation bond valence of ZnTiNb2O8. The τf variation is affected by the variation of each phase, and the variation of (Zn0.75Ti0.25)(Nb0.75Ti0.25)2O6 played a more important role. The typical values of ε=33.84, Qf=31,000 GHz, τf=−67.91×10−6/°C were obtained for ZnTi(Nb1−xSbx)2O8 (x=0.05) specimens sintered at 1100 °C for 6 h.