Sintering Process Influence on Microstriicture and Intergraniilar Impedance of Rare-Earth Modified BaTiO_3-Ceramics

摘要

Sintering process is a complex of different synergetic effects during the ceramics materials consolidation. The microstructurul level properties control is very important as a stage in advanced materials prognosis. SEM analysis of Yb/BaTiO_3 doped ceramics showed that in samples doped with a low level of dopant and sintered at higher temperatures the grain size ranged from 10-60 ìm, while with the higher dopant concentration the grain size ranged between 2-15 ìm. The morphology of sintered BaTiO_3--ceramics grains points out the validity of developing new structure analytical methods based on different geometries of grains' model systems. The idea of electrical properties of BaTiO_3ceramics being influenced by intergrain microcontacts can be successfully followed if we start with the two-sphere Coble's model and also the correction of the Coble's model. In this paper, the grains contact models based on spherical, ellipsoidal and polyhedral geometries are presented making a new modeling tool for structure research of BaTiO_3ceramics materials. Intergranular impedance analysis of grains clusters was also introduced. Obtained results enabled establishment of interrelation between structural and electrical parameters.