scholarly journals Processing and characterization of lead-free ceramics on the base of sodium–potassium niobate

2018 ◽  
Vol 08 (01) ◽  
pp. 1850004 ◽  
Author(s):  
E. D. Politova ◽  
N. V. Golubko ◽  
G. M. Kaleva ◽  
A. V. Mosunov ◽  
N. V. Sadovskaya ◽  
...  

Lead-free sodium–potassium niobate-based piezoelectric materials are most intensively studied in order to replace the widely used Pb-based ones. In this work, the effects of modification of compositions by donor and acceptor dopants in the A- and B-sites of perovskite lattice on structure, dielectric, ferroelectric, and piezoelectric properties of ceramics from Morphotropic Phase Boundary in the ([Formula: see text])(K[Formula: see text]Na[Formula: see text])NbO3–[Formula: see text]BaTiO3 system and in compositions with [Formula: see text] and 0.06 additionally doped by Ni[Formula: see text] cations have been studied.

2010 ◽  
Vol 03 (01) ◽  
pp. 15-18 ◽  
Author(s):  
MARIJA KOSEC ◽  
BARBARA MALIČ ◽  
ANDREJA BENČAN ◽  
TADEJ ROJAC ◽  
JENNY TELLIER

In this review, the crystal structure and the synthesis of the sodium potassium niobate ( K 0.5 Na 0.5 NbO 3) as a promising candidate for lead-free piezoelectrics are addressed. The sintering and the microstructure as prerequisites for obtaining ceramics with reliable and sufficiently high piezoelectric properties for selected applications are discussed.


Ceramics ◽  
2019 ◽  
Vol 2 (3) ◽  
pp. 460-471 ◽  
Author(s):  
Astri Bjørnetun Haugen

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.


2011 ◽  
Vol 50 (9) ◽  
pp. 09ND09 ◽  
Author(s):  
Kiyoshi Kanie ◽  
Hideto Mizutani ◽  
Atsuki Terabe ◽  
Yoshiki Numamoto ◽  
Shintaro Tsukamoto ◽  
...  

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