Piezoelectric properties and temperature sensitivity for CaZrO3 doped KNN-based ceramics sintered in reducing atmosphere

Lead-free MnO doped 0.955K0.5Na0.5NbO3-0.045Bi0.5Na0.5ZrO3(abbreviate as KNN-0.045BNZ) ceramics have been prepared by a conventional solid-state sintering method in a reducing atmosphere. The addition of MnO suppresses grain growth and eliminates the liquid phase. MnO dopant changes the crystalline structures of KNN-0.045BNZ ceramics from the classical Morphotropic Phase Boundary (MPB) with rhombohedral phase (R) and tetragonal phase (T) to the suppressed MPB with R/T phase. The 0.4% MnO doped KNN-0.045BNZ ceramics show an excellent electrical properties with quasi static piezoelectric constantd33=300 pC/N, Curie temperatureTC= 350 °C, insulation resistivity ρ=4.83 × 1011(Ω・cm), and high field piezoelectric constants =438 pm/V (atEmax= 25 kV/cm). The results indicate that the 0.4%Mn doped KNN-0.045BNZ ceramic is a promising lead-free piezoelectric candidate material for commercial applications.

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Defect control for enhanced piezoelectric properties in SnO 2 and ZrO 2 co-modified KNN ceramics fired under reducing atmosphere

Journal of the European Ceramic Society ◽

10.1016/j.jeurceramsoc.2016.12.040 ◽

2017 ◽

Vol 37 (5) ◽

pp. 2057-2065 ◽

Cited By ~ 21

Author(s):

Yu Huan ◽

Xiaohui Wang ◽

Tao Wei ◽

Peiyao Zhao ◽

Jing Xie ◽

...

Keyword(s):

Piezoelectric Properties ◽

Reducing Atmosphere ◽

Defect Control

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Improving fatigue properties, temperature stability and piezoelectric properties of KNN-based ceramics via sintering in reducing atmosphere

Journal of the European Ceramic Society ◽

10.1016/j.jeurceramsoc.2021.03.007 ◽

2021 ◽

Author(s):

Zhenyong Cen ◽

Zhihao Dong ◽

Ze Xu ◽

Fang-Zhou Yao ◽

Limin Guo ◽

...

Keyword(s):

Piezoelectric Properties ◽

Temperature Stability ◽

Fatigue Properties ◽

Reducing Atmosphere

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Simultaneously improving piezoelectric properties and temperature stability of Na0.5K0.5NbO3 (KNN)-based ceramics sintered in reducing atmosphere

Journal of Advanced Ceramics ◽

10.1007/s40145-021-0475-0 ◽

2021 ◽

Author(s):

Zhenyong Cen ◽

Shuaishuai Bian ◽

Ze Xu ◽

Ke Wang ◽

Limin Guo ◽

...

Keyword(s):

Grain Size ◽

Alkali Metal ◽

Oxygen Vacancies ◽

Piezoelectric Properties ◽

Temperature Stability ◽

Conventional Solid State Reaction ◽

Sintering Aid ◽

Reducing Atmosphere ◽

Piezoelectric Strain ◽

Free Material

AbstractIt is a very difficult work to sinter K0.5Na0.5NbO3 (KNN)-based materials with good reduction resistance in strong reducing atmosphere. 0.945K0.48Na0.52Nb0.96Ta0.04O3−0.055BaZrO3 + 0.03ZrO2 + y mol%MnO (KNNT−0.055BZ + 0.03Zr + yMn) ceramics sintered in reducing atmosphere were prepared successfully by conventional solid-state reaction methods. MnO dopant increases grain size at y = 5–8 due to strong lattice distortion and then decreases grain size at y = 9 due to much Mn4Nb2O9 accumulated at the grain boundary. MnO dopant as an excellent sintering aid can effectively reduce volatilization of alkali metal by decreasing the sintering temperature (Tsinter). Reducing alkali metal volatilization can greatly reduce oxygen vacancies and improve piezoelectric properties. MnO dopant can improve the anti-reduction properties. The KNNT−0.055BZ + 0.03Zr + yMn ceramics at y = 6–9 show outstanding anti-fatigue of unipolar piezoelectric strain under the synergistic effect of reduced oxygen vacancies due to reduced volatilization and increased grain size. Piezoelectric properties and temperature stability of KNNT−0.055BZ + 0.03Zr ceramics sintered in reducing atmosphere are improved simultaneously by MnO dopant. Optimum inverse piezoelectric coefficient (d 33 * ) of ceramics at y = 8 reaches up to 480 pm/V under low driving electric field E = 20 kV/cm at room temperature, and its temperature stability of d 33 * reaches 158 °C. It will be an excellent lead-free material candidate for the preparation of multilayer piezoelectric actuators co-fired with nickel electrode.

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