scholarly journals Особенности поляризации пьезоэлектрической керамики на основе ниобата натрия

2021 ◽  
Vol 63 (11) ◽  
pp. 1890
Author(s):  
О.В. Малышкина ◽  
М. Али ◽  
А.И. Иванова ◽  
И.А. Чернышова ◽  
Д.В. Мамаев
Keyword(s):  
Ferroelectric Properties ◽  
Structural Features ◽  
Potassium Niobate ◽  
Sodium Niobate ◽  
Chemical Formula ◽  
Sodium Potassium ◽  
X Ray ◽  
Sodium Potassium Niobate ◽  
Ceramic Samples ◽  
Additional Phase

Comparative studies of the pyroelectric properties and structural features of sodium niobate and sodium-potassium niobate ceramics obtained under different technological conditions for the synthesis of sodium niobate have been carried out. X-ray phase analysis revealed the existence of an additional phase with the chemical formula NaNb10O18 in sodium niobate ceramic samples that do not exhibit ferroelectric properties. It is shown that the temperature conditions for the synthesis of the sodium niobate material determine the nature of the macroscopic polarization of the samples of both pure sodium niobate and sodium-potassium niobate.

Effect of Silver Electrode Annealing Temperature on Electrical Properties of Sodium Potassium Niobate Based Ceramics

2018 ◽  
Vol 48 (2) ◽  
pp. 845-852 ◽  
Author(s):  
N. N. Wathore ◽  
Bhupender Rawal ◽  
Prashant Dixit ◽  
Snehal Mandave ◽  
B. Praveenkumar ◽  
...  
Keyword(s):  
Electrical Properties ◽  
Annealing Temperature ◽  
Silver Electrode ◽  
Potassium Niobate ◽  
Sodium Potassium ◽  
Sodium Potassium Niobate

Influence MnO2 on the Properties of (LixNayK1-x-y)NbO3 Ceramics

2007 ◽  
Vol 336-338 ◽  
pp. 199-202
Author(s):  
Qiang Chen ◽  
De Jun Lan ◽  
Yi Chen ◽  
Du Min Lin ◽  
Xi Yue ◽  
...  
Keyword(s):  
Composition Range ◽  
Sintering Temperature ◽  
Mechanical Quality Factor ◽  
Piezoelectric Constant ◽  
Potassium Niobate ◽  
Sodium Potassium ◽  
Sodium Potassium Niobate ◽  
State Process ◽  
Mechanical Quality ◽  
Curie Temperature Tc

Lead-free piezoelectric ceramics lithium sodium potassium niobate (LixNayK1-x-y)NbO3 (LNKN100x/100y) have been synthesized by a conventional solid state process. The effects of MnO2 addition on the properties of (LixNayK1-x-y)NbO3(x=0.06, y=0.5)(LNKN6/50) ceramics were investigated. It was found that a morphotropic phase boundary (MPB) between orthorhombic and tetragonal phases is in the composition range 0.05<x<0.07. The piezoelectric constant d33 and the planar electromechanical coefficient kp of LNKN6/50 ceramics reach 222pC/N and 39%, respectively. As the amount of MnO2- doped increases, dielectric constant, piezoelectric constant and Curie temperature Tc of LNKN:Mn ceramics decreased, while mechanical quality factor Qm of LNKN6/50:Mn increased prominently compared to pure LNKN6/50 ceramics. The addition of MnO2 can also decrease the sintering temperature effectively of LNKN6/50 ceramics.

scholarly journals Hybrid Atmosphere Processing of Lead-Free Piezoelectric Sodium Potassium Niobate-Based Ceramics

Ceramics ◽  
2019 ◽  
Vol 2 (3) ◽  
pp. 460-471 ◽  
Author(s):  
Astri Bjørnetun Haugen
Keyword(s):  
Lead Free ◽  
Piezoelectric Response ◽  
Potassium Niobate ◽  
Sodium Potassium ◽  
New Approach ◽  
Sodium Potassium Niobate ◽  
Phase Pure ◽  
High Alkali ◽  
Surface Decomposition ◽  
Air Processing

K0.5Na0.5NbO3-based ceramics, a promising group of lead-free piezoelectrics, are challenging to sinter dense while avoiding alkali evaporation. This work explores hybrid atmosphere processing, a new approach where reducing atmospheres is used during heating to avoid coarsening from alkali carbonates and hydroxides, and oxidizing atmospheres is used during sintering to avoid alkali evaporation. Discs of Li0.06(K0.52Na0.48)0.94Nb0.71Ta0.29O3 with 0.25 mol% Mn (KNNLTM) were sintered in air, N2, 9% H2 in N2, or 9% H2 in N2 during heating and air during sintering (hybrid atmosphere processing). The highest density was obtained by sintering in 9% H2 in N2, but resulted in high alkali loss and decomposition of the surface, followed by low piezoelectric response. However, with the hybrid H2/air processing it was possible to both avoid surface decomposition and leakage currently associated with alkali evaporation during sintering in H2, and to obtain a denser, more phase-pure and small-grained KNNLTM ceramic with a higher piezoelectric response than obtained by sintering in air or N2.

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