Nonreducible lead-free (Ba,Ca)TiO3 piezoceramics were fabricated by controlling the level of Mn doping. Similar to Mn-doped (Ba0.85Ca0.15)TiO3 ceramics sintered in air, stable dielectric properties with temperature change were achieved for the nonreducible sample by stabilizing the tetragonal phase of BaTiO3 over a wide temperature range. In addition, optimization of the level of Mn doping was very effective in improving the sintered density and electrical resistivity for (Ba0.85Ca0.15)TiO3 ceramics sintered under a low oxygen partial pressure. The valence state of doped Mn in nonreducible (Ba,Ca)TiO3 after sintering was confirmed to be Mn2+ or Mn3+ by electron spin resonance analysis. Sintered bodies of 1 mol% Ba excess and 1 mol% Mn-doped (Ba0.85Ca0.15)TiO3, which were sintered at 1350 °C in a H2(0.3%)/Ar atmosphere, exhibited sufficient sintered density and resistivity to allow the characterization of several electrical properties. The ferroelectric, field-induced strain, and piezoelectric properties of the nonreducible (Ba0.85Ca0.15)TiO3 ceramics sintered in the reducing atmosphere were comparable with those of (Ba0.85Ca0.15)TiO3 samples sintered in air.
All Science Journal Classification (ASJC) codes
- Electronic, Optical and Magnetic Materials
- Ceramics and Composites
- Process Chemistry and Technology
- Surfaces, Coatings and Films
- Materials Chemistry