Effect of MnO on the Phase Development, Microstructures, and Dielectric Properties of 0.95Na0.5K0.5NbO3–0.05LiTaO3 Ceramics


  • Y. Saito—contributing editor

  • This work was financially supported by Thailand Research Fund (TRF) and Commission on Higher Education, and the National Nanotechnology Center (NANOTEC), NSTDA, Ministry of Science and Technology, Thailand, through its program of Center of Excellence Network.

†Author to whom correspondence should be addressed. e-mail: ppornsuda@yahoo.com


Lead-free piezoelectric ceramics in the system 0.95Na0.5K0.5NbO3–0.05LiTaO3 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.