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Phase Formation and Enhanced Dielectric Response of Y 2/3 Cu 3 Ti 4 O 12 Ceramics Derived from the Sol–Gel Process
Author(s) -
Li Junwei,
Liang Pengfei,
Yi Jing,
Chao Xiaolian,
Yang Zupei
Publication year - 2015
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/jace.13355
Subject(s) - dielectric , materials science , ceramic , analytical chemistry (journal) , microstructure , sol gel , grain size , activation energy , phase (matter) , mineralogy , oxygen , composite material , chemistry , nanotechnology , chromatography , optoelectronics , organic chemistry
Y 2/3 Cu 3 Ti 4 O 12 (YCTO) ceramics were successfully synthesized by sol–gel method (SG) and solid‐state method (SS), respectively. The optimized processing parameters for the syntheses of precursor powders by sol–gel process were determined as follows: the Ti ( OC 4 H 9 ) 4 concentration was 0.50 mol/L, the CH 3 COOH volume was 8 mL, and the volume percentage of H 2 O was 11.2%. Particularly, on the basis of XRD and TG‐DSC analyses, the phase formation temperature of YCTO‐SG was at least 100°C lower than that of YCTO‐SS. YCTO‐SG ceramics sintered at 1060°C for 25 h showed fine‐grained microstructure, and higher dielectric constant (ε ′ ≈ 5.24 × 10 4 ) at 1 kHz compared to YCTO‐SS ceramics (ε ′ ≈ 0.93 × 10 4 ). The higher dielectric constant of the YCTO‐SG ceramics was attributed to the grain size effect. Furthermore, the YCTO‐SG ceramics showed a distinct high‐temperature (>300°C) relaxor‐like behavior. According to the calculated activation energy value, the single ionization of oxygen vacancies was responsible for the conduction and dielectric anomaly behaviors of YCTO‐SG ceramics.