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Phase Transitions in Nanocrystalline Barium Titanate Ceramics Prepared by Spark Plasma Sintering
Author(s) -
Deng Xiangyun,
Wang Xiaohui,
Wen Hai,
Kang Aiguo,
Gui Zhilun,
Li Longtu
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.1551-2916.2005.00836.x
Subject(s) - spark plasma sintering , materials science , nanocrystalline material , ceramic , ferroelectricity , crystallite , barium titanate , piezoresponse force microscopy , raman spectroscopy , grain size , sintering , grain growth , composite material , mineralogy , nanotechnology , dielectric , metallurgy , optoelectronics , optics , chemistry , physics
The bulk dense nanocrystalline BaTiO 3 (BT) ceramics ranging from 20 to 100 nm have been successfully prepared by the spark plasma sintering (SPS) method. Raman spectra and X‐ray diffraction were used in combination with electron microscopy to study the evolution of lattice structure and phase transformation behavior with grain growth from nanoscale to micrometer scale for BT ceramics. The results reveal that the SPS technique provides exceptional opportunity to compact ceramics to full density with nanograin size. It is also demonstrated that all structural modifications in nanocrystalline BT and low‐symmetry structures still exist in 20 nm nanograin BT ceramics. The ferroelectric properties of crystalline structures were investigated by scanning force microscopy in piezoresponse mode. Piezoelectric hysteresis loop was recorded, demonstrating that 20 nm BT ceramics has a remanent polarization and is switchable by an electric field. Thus, if a critical grain size exists for ferroelectricity, it is less than 20 nm for polycrystalline BT ceramics.