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Microstructural Evolution of Crystalline‐Oriented (K 0.5 Na 0.5 )NbO 3 Piezoelectric Ceramics with a Sintering Aid of CuO
Author(s) -
Takao Hisaaki,
Saito Yasuyoshi,
Aoki Yoshifumi,
Horibuchi Kayo
Publication year - 2006
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.1551-2916.2006.01042.x
Subject(s) - sintering , materials science , ceramic , natural bond orbital , piezoelectricity , transmission electron microscopy , relative density , microstructure , grain growth , mineralogy , crystallography , composite material , nanotechnology , density functional theory , chemistry , computational chemistry
The microstructural development of crystalline‐oriented (K 0.5 Na 0.5 )NbO 3 (KNN)‐based piezoelectric ceramics during sintering was investigated. The addition of CuO as a sintering aid was found to be effective for fabricating highly oriented and dense KNN ceramics. KNN specimens containing 0.5–1.0 mol% CuO sintered at 1100°C for 1 h were found to have relative densities and pseudo‐cubic {100} orientation degrees of 95% or higher. In the early stages of sintering, KNN is formed in the reaction between complementary reactants NaNbO 3 and KNbO 3 , after which oriented grain growth proceeds at a relative density of more than 90%. In addition, the results of transmission electron microscopy observation showed that textured KNN ceramics have a unique pectinate‐like domain structure with domain walls consisting of {101} planes.