Effect of Bi4Zr3O12 on the properties of (KxNa1-x)NbO3 based ceramics

Abstract

KNN-based ceramics modified with small amounts of Bi4Zr3O12 (BiZ) has been synthesized using high-throughput experimentation (HTE). The results from X-ray diffraction show that for samples with base composition (K0.5Na0.5)NbO3 (KNN), the phase present changes from orthorhombic to pseudo-cubic with more than 0.2 mol% BiZ addition; for samples with base composition (K0.48Na0.48Li0.04)(Nb0.9Ta0.1)O3 (KNNLT), the phase present changes from a mixture of orthorhombic and tetragonal symmetry to pseudo-cubic with more than 0.4 mol % while for samples with base composition (K0.48Na0.48Li0.04)(Nb0.86Ta0.1Sb0.04)O3 (KNNLST), the phase present is tetragonal with < 0.3 mol% BiZ addition and transforms to pseudo-cubic with more dopant addition. The microstructures of the samples show that addition of BiZ decreases the average grain size and increases the volume of pores at the grain boundaries. The values of dielectric constant for KNN and KNNLT compositions increase slightly with BiZ addition while that for KNNLST decreases gradually with BiZ addition. The dielectric loss values are between 0.02 and 0.04 for KNNLT and KNNLST compositions while they are ˜ 0.05 for KNN samples. The resistivity values increases with BiZ addition and values in the range of 1010 ω