Revealing the influence of Nb-doping on the crystal structure and electromechanical properties of (K, Bi)(Mg, Ti, Nb)O3 ceramics
Nb-modified lead-free ceramics (K 0.48 Bi 0.52 )(Mg 0.02 Ti 0.98− x Nb x )O 3 , (KBT-BMTNb x with x = 0.00 − 0.05) were synthesized by a conventional solid-state reaction route followed by furnace cooling. The effects of Nb-doping on the structural properties and electrical properties of KBT-BMTNb...
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Veröffentlicht in: | Journal of electroceramics 2023-10, Vol.51 (2), p.122-132 |
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Hauptverfasser: | , , , , , , , , , , , , , , |
Format: | Artikel |
Sprache: | eng |
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Zusammenfassung: | Nb-modified lead-free ceramics (K
0.48
Bi
0.52
)(Mg
0.02
Ti
0.98−
x
Nb
x
)O
3
, (KBT-BMTNb
x
with
x
= 0.00 − 0.05) were synthesized by a conventional solid-state reaction route followed by furnace cooling. The effects of Nb-doping on the structural properties and electrical properties of KBT-BMTNb
x
ceramics have been investigated. The X-ray diffraction pattern indicates a mixed tetragonal and cubic phase for the pure KBT-BMTNb
x
ceramics. Therefore, a large piezoelectric actuator coefficient
d
33
*
≈ 700 pm/V, piezoelectric sensor coefficient (
d
33
≈ 133 pC/N) along with remnant polarization (
P
r
≈ 17.5 µC/cm
2
), maximum electromechanical strain ≈ 0.35% and maximum temperature (
T
m
≈ 336 ºC) were obtained for KBT-BMTNb
x
. However, with Nb-doping, a compositionally driven phase transformation occurred from mixed rhombohedral and tetragonal phases to cubic phase. Because of the excess Nb-doping in the KBT-BMT ceramics, the grain size suddenly decreased, as a result, the long-range ferroelectric phase was converted into a short-range relaxor phase. Hence, a low dielectric loss
tan
δ ≈ 0.02 was achieved at
x
= 0.02 composition. This superior dielectric performance is correlated to the crystal structure morphotropic phase boundary, optimum grain size (≈ 2 μm), maximum lattice distortion, and soft-ferroelectric effect induced by the donor doping. The main aim of recent research is to investigate
P
r
,
d
33
,
d
33
*
,
S
max,
and reduced tanδ for practical applications in the real world. |
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ISSN: | 1385-3449 1573-8663 |
DOI: | 10.1007/s10832-023-00321-1 |