【摘要】 The Mn-doped barium titanate nanosized powders and ceramics were prepared via the sol-gel process. The powders and ceramics were characterized by XRD,SEM and TEM. The dielectric properties of the ceramics were also measured. The influences of calcination temperature and Mn concentration on the microstructure,dielectric properties and phase composition of BaTiO3 nano-powders and ceramics were discussed. The results indicated that the BaTiO3-based powders doped with 1.0mol% Mn were mainly in cubic BaTiO3 phase,but the tetragonal phase became more evident when the calcination temperature increased. After sintering,Mn-doped ceramics were mainly composed of cubic BaTiO3. Specially,a new phase of hexagonal crystal BaTiO3 and BaMnO3 existed in the ceramics doped with 5.0mol% Mn and the ceramic grains were in ‘clintheriform’. The structure of ‘clintheriform’ led to the poor densification of ceramics,reducing the dielectric constant obviously. The dielectric constants of BaTiO3 ceramics first increased and then decreased as the Mn concentration increased. The room temperature dielectric constant was 2290 and the lowest dielectric loss was 0.004 when the Mn concentration was 0.5mol%.更多还原

【Abstract】 The Mn-doped barium titanate nanosized powders and ceramics were prepared via the sol-gel process. The powders and ceramics were characterized by XRD,SEM and TEM. The dielectric properties of the ceramics were also measured. The influences of calcination temperature and Mn concentration on the microstructure,dielectric properties and phase composition of BaTiO3 nano-powders and ceramics were discussed. The results indicated that the BaTiO3-based powders doped with 1.0mol% Mn were mainly in cubic BaTiO3 phase,but the tetragonal phase became more evident when the calcination temperature increased. After sintering,Mn-doped ceramics were mainly composed of cubic BaTiO3. Specially,a new phase of hexagonal crystal BaTiO3 and BaMnO3 existed in the ceramics doped with 5.0mol% Mn and the ceramic grains were in ‘clintheriform’. The structure of ‘clintheriform’ led to the poor densification of ceramics,reducing the dielectric constant obviously. The dielectric constants of BaTiO3 ceramics first increased and then decreased as the Mn concentration increased. The room temperature dielectric constant was 2290 and the lowest dielectric loss was 0.004 when the Mn concentration was 0.5mol%.更多还原