Doping Modification Of (Zr_0.8Sn_0.2)TiO₄ Microwave Dielectric Ceramics

(Zr0.8Sn0.2)TiO4(ZST)ceramics have been widespread concerned and used in the filters,resonators,oscillators and other microwave devices in recent years.due to their close to zero resonant frequency temperature coefficient,moderate high frequency dielectric constant,and a high quality factor.However,since the sintering temperature of the ZST ceramic is as high as 1600?,it is not well compatible with the built-in electrode layer under the melting temperature of the metal conductor.On the basis of reducing the sintering temperature of ZST ceramics,improving their dielectric properties and microwave performance have become a hotspot.ZST ceramics were prepared by traditional oxide solid phase sintering method,and the sintering temperature of ZST ceramics was effectively reduced by doping ZnO.The effects of ZnO doping on the sintering characteristics,phase structure,microstructure and dielectric properties of the ceramics were investigated by XRD and SEM.The results show that the ZST ceramics were sintered compactly with 2 wt%ZnO at 1350?.The main crystal phase is(Zr0.8Sn0.2)TiO4 phase with ?-PbO2 structure,dielectric constant ? = 40.8,dielectric loss tan? =8.87 × 10-5,quality factor Q×f=8402.9 GHz(4.721 GHz).On the basis of this,in order to improve the properties of ceramics,ZST ceramics were doped with CuO/ZnO(ZC),JLa2O3/ZnO(ZL)and Bi2O3/ZnO(ZB)binary composite,the ZST ceramics were sintered compactly at 1250? for 2 h.Reducing the sintering temperature of the ZST ceramic sample.The effects of ZC,ZL and ZB doping on the sintering characteristics,phase structure,microstructure and dielectric properties of ceramics were studied by XRD and SEM.The results show that,the main crystal phase of ZST ceramics doping 2 wt%Bi2O3 + 2 wt%ZnO is the(Zr0.8Sn0.2)TiO4 phase with the ?-PbO2 structure at 1250 ? for 2 h.The dielectric properties of ceramics is:??43.8,tan?= 2.21 × 10-5,Q × f=14593.8 GHz(4.788 GHz).In order to reduce the vacancy and defects caused by the imbalance of ion electricity price,this paper chooses Nb2O,/Cr2O3 and Ga2O3/Sb2O5 to equimolar doping modification on the basis of reducing the sintering temperature of ZST ceramics.ZST ceramics were successfully prepared by traditional solid phase sintering method,and the dielectric properties of the samples were tested.The mechanism of doping was analyzed by combining the phase structure,sintering property and microstructure analysis.It was found that when the 0.25 mol%Nb2O5 + 0.25 mol%Cr2O3 was doped,the main crystal phase was(Zr0.8Sn0.2)TiO4 phase with a-PbO2 structure,the sintering temperature was 1350 ?,the ceramic has the best microwave dielectric performance:? = 47.6,tan?=1.34 ×10-5,Q×f= 23533.8 GHz(4.795 GHz).