Synthesis And Dielectric Properties Of Niobate Yttrium

Niobate rare earth ceramics(LnNbO₄)(Ln representatives La to Lu including Y)is a series of new functional ceramic materials with similar structural phase transition characteristics.When Ln is replaced by Y,it is called Niobate Yttrium (YNbO₄)ceramics.This paper is focused on YNbO₄,including relationship between preparation technology,microscopic structure and dielectric properties and a series of technical problems.The main raw material applied in our work are yttrium oxide(Y₂O₃)and niobium oxide(Nb₂O₅),High purity YNbO₄ ceramic using solid-phase reaction at the molar ratio Y₂O₃:Nb₂O₅ =1:1 in the reaction atmosphere protection.The optium reaction synthesis temperature is 1100℃to 1350℃.At sintering temperature1350℃,we obtained YNbO₄ ceramic with dielectric constant:26,dielectric loss:5.4×10^-5and Q×f value:3.4×10⁴GHz.By additive calcium fluoride(CaF₂),YNbO₄ microwave dielectric ceramics properties were studied from the doping amount to holding time,sintering temperature,and the effect of CaF₂ doping on its sintering behavior,crystal structure,microscopic morphology,microwave dielectric properties.The results showed that adding of CaF₂,YNbO₄ sintering temperature reduced and microwave dielectric properties improved.When doping CaF₂ in weight reached 2.0wt%,dielectric constant reach 498, dielectric loss reach 2.1×10^-4,Q×fvalue reach 2.1×10³GHz.Enhanced YNbO₄ density and dielectric properties is by hot-pressing sintering method.doping 2.0wt%CaF₂,YNbO₄ microwave dielectric constant reach 501,dielectric loss reach 1.1×10^-3and Q×fvalue reach 2.4×10³GHz GHz.