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Phase Diagram and Enhanced Piezoelectric Response of Lead‐Free BaTiO 3 – CaTiO 3 – BaHfO 3 System
Author(s) -
Wang Dali,
Jiang Zhaohua,
Yang Bin,
Zhang Shantao,
Zhang Mingfu,
Guo Feifei,
Cao Wenwu
Publication year - 2014
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.13137
Subject(s) - phase boundary , phase diagram , phase (matter) , analytical chemistry (journal) , materials science , crystallography , ternary operation , mineralogy , chemistry , organic chemistry , chromatography , computer science , programming language
Three composition groups in the BaTiO 3 – CaTiO 3 – BaHfO 3 ternary system, (1 − x ) Ba ( Hf y Ti 1− y ) O 3 – x ( Ba 1− z Ca z ) TiO 3 (abbreviated as BH y T – x BC z T with x = 0–1.0, y = 0.16, z = 0.20; x = 0–1.0, y = 0.16, z = 0.30; x = 0–1.0, y = 0.20, z = 0.30, respectively), have been designed for investigating the variation of the intermediate O‐phase region and its effect on the electrical properties. The temperature‐composition phase diagram of each group has been proposed based on the X‐ray diffraction patterns and the temperature‐dependent dielectric behaviors. The enhanced piezoelectric properties are achieved in the O–T phase boundary compositions of the three groups, which are BH 0.16 T –0.58 BC 0.20 T , BH 0.16 T –0.48 BC 0.30 T and BH 0.20 T –0.53 BC 0.30 T , respectively. Piezoelectric coefficient d 33 of 448 pC/N is obtained in BH 0.20 T –0.53 BC 0.30 T , which is higher than those of the other two phase boundary compositions. The O‐phase zone in BH 0.20 T – x BC 0.30 T is narrower than those in the BH 0.16 T – x BC 0.20 T and BH 0.16 T – x BC 0.30 T . In spite of its small O‐phase volume occupancy, the O‐phase plays a key role in the properties of the system. Our work confirms that the enhancement in piezoelectric properties is not only related to the O–T phase boundary near room temperature ( RT ), but also related to the shift of T R‐O toward RT . In addition, a quantitative relation between the phase boundary composition and atomic mole ratio of Hf to Ca ( R m ) is proposed, which the R m value corresponding to the phase boundary is about 0.58. The results clearly demonstrate that in this system high piezoelectric properties are achieved by tuning the specific R m value. Such a work may provide new clues for designing lead‐free piezoelectric materials with enhanced piezoelectric property.