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Grain Boundaries of Semiconducting SrTiO 3 and BaTiO 3 Ceramics Synthesized from Surface‐Coated Powders
Author(s) -
Park MyungBeom,
Cho NamHee
Publication year - 2001
Publication title -
journal of the american ceramic society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.9
H-Index - 196
eISSN - 1551-2916
pISSN - 0002-7820
DOI - 10.1111/j.1151-2916.2001.tb00940.x
Subject(s) - grain boundary , materials science , ceramic , crystallite , electrical resistivity and conductivity , sintering , coating , grain size , composite material , mineralogy , metallurgy , microstructure , electrical engineering , chemistry , engineering
The chemical and electrical features of the grain boundaries in polycrystalline SrTi 0.99 Nb 0.01 O 3 (ST) and BaTiO 3 (BT) ceramics, which were synthesized by hot‐press sintering Na‐ and Mn‐coated semiconducting ST and BT powders, respectively, were investigated. Because of the excess negative electric charges formed near grain boundaries, electrostatic potential barriers were formed near the grain boundaries. The electrical features of the grain boundaries in ceramics are very sensitive to the amount of the coating material. When the amount of the coating material was increased from 0 to 5 wt%, the threshold voltage of the ST ceramics and the resistivity jump ratio of the BT ceramics increased from 0.7 to 81.0 V/cm and from 1.0 to 2.0 × 10 3 , respectively. The electrical features of the grain boundaries are related to their chemical characteristics.