Effect of MnO on the Phase Development, Microstructures, and Dielectric Properties of 0.95Na 0.5 K 0.5 NbO 3 –0.05LiTaO 3 Ceramics

Lead‐free piezoelectric ceramics in the system 0.95Na 0.5 K 0.5 NbO 3 –0.05LiTaO 3 were modified with ≤1 mol% MnO. Maximum densities occurred at a sintering temperature of 1050°C. Characteristic changes in the relative intensity of X‐ray diffraction peaks were consistent with Mn ions substituting on the perovskite lattice to produce a change from orthorhombic to a mixture of tetragonal and orthorhombic phases. Grain growth during secondary recrystallization was also affected, leading to increased grain sizes. The dielectric constant increased from ∼600 in unmodified ceramics to ∼1040 in ceramics prepared with 0.5 mol% MnO.