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Design on improving piezoelectric strain and temperature stability of KNN‐based ceramics
Author(s) -
Cen Zhenyong,
Feng Wei,
Zhao Peiyao,
Chen Lingling,
Zhu Chaoqiong,
Yu Yan,
Li Longtu,
Wang Xiaohui
Publication year - 2019
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.16136
Subject(s) - materials science , phase boundary , ceramic , sintering , piezoelectricity , piezoelectric coefficient , orthorhombic crystal system , analytical chemistry (journal) , tetragonal crystal system , atmospheric temperature range , phase (matter) , grain size , dopant , grain growth , grain boundary , phase transition , doping , composite material , mineralogy , crystallography , microstructure , thermodynamics , crystal structure , chemistry , optoelectronics , physics , organic chemistry , chromatography
Lead‐free 0.99(0.96K 0.46 Na 0.54 Nb 1‐ x Ta x O 3 ‐0.04Bi 0.5 (Na 0.82 K 0.18 ) 0.5 ZrO 3 )‐0.01CaZrO 3 (0.99(0.96KNNTa x ‐0.04BNZ)‐0.01CZ) ceramics were prepared by a solid‐state sintering method. Ta 2 O 5 doped in the 0.99(0.96KNNTa x ‐0.04BNZ)‐0.01CZ ceramics results in a phase structure transition from the orthorhombic (O)/tetragonal (T) phase to the rhombohedral (R)/T phase. The Ta 2 O 5 dopant induces a decrease in the average grain size from ~1.70 to ~0.69 μm. At x = 0.02 and 0.04, the ceramics have a high reverse piezoelectric coefficient (~500 pm/V under 25 kV/cm). The ceramics with x = 0.04 show an optimal level of unipolar strain, reaching 0.17% under 35 kV/cm at room temperature, and their field‐induced strain varies <10% in the temperature range from 25 to 135°C. The presence of the O phase in the polymorphic phase boundary (PPB) improves the temperature stability the reverse piezoelectric coefficient ( d 33 ∗ ). Obtaining KNN‐based ceramics with good piezoelectric properties and weak temperature sensitivity by designing a R/O/T phase boundary and controlling the average grain size to the submicrometer level is highly feasible.