Effects Of Co-Doping Of Sr Element And Knn Group On The Dielectric Properties Of Bnt-Bt Ceramics

(1-x)Bi1/2Na1/2TiO3-xBa(1/2)Sr(1/2)TiO(3)-0.05KNaNbO(3)(BNT-BST-KNN, x = 0.01, 0.03,0.05,0.07) lead-free anti-ferroelectric ceramics were synthesized by a conventional solid-state. The effects of co-doping of Sr element and KNN group on phase structures, compositional distribution and electrical properties of BNT-BST-KNN ceramics were systematically investigated to further understand the mechanism of phase transition. It was found that the grain size decreased obviously, indicating that the addition of Sr element inhibited the grain growth. According to SEM and XRD analysis, the components of the samples obtained were all perovskite phase structure, and the coke free green stone was equal to other heterophases, indicating that K1+, Na1+, Nb4+ and Sr2+ ions successfully diffused into the crystal lattice of BiNaTiO3-BaTiO3 and formed a uniform solid solution. It shows that the doping of Sr element and KNN effectively promotes the transformation of trigonal phase to tetragonal phase. From the analysis results, the doping of Sr element and KNN effectively reduces the dielectric loss of the materials, and the dielectric property stability is greatly improved.