scholarly journals Mechanochemically-Assisted Synthesis of Lead-Free Piezoelectric CaZrO3-Modified (K,Na,Li)(Nb,Ta)O3-Solid Solution

Ceramics ◽  
2018 ◽  
Vol 1 (2) ◽  
pp. 304-318 ◽  
Author(s):  
Kristian Radan ◽  
Brigita Kmet ◽  
Silvo Drnovšek ◽  
Uroš Prah ◽  
Tadej Rojac ◽  
...  

Lead-free piezoelectric 0.95(Na0.49K0.49Li0.02)(Nb0.8Ta0.2)O3–0.05CaZrO3 with 2 wt % MnO2 addition was prepared using mechanochemically-assisted solid-state synthesis. Upon mechanochemical activation of the mixture of reagents partial amorphization occurs which contributes to a significantly lower temperature of completion of the solid-state reaction, ~600 °C as opposed to ~700 °C for the conventional solid-state synthesis as determined by thermal analysis. The ceramic specimens prepared by the mechanochemically-assisted route exhibit improved compositional homogeneity and slightly enhanced piezoelectric properties, achieved in a considerably shorter processing time compared to the conventional solid-state synthesis route, which was studied as a reference.

2014 ◽  
Vol 87 ◽  
pp. 12-17
Author(s):  
Fares Kahoul ◽  
Louanes Hamzioui ◽  
Ahmed Boutarfaia

The phase structure, microstructure and electrical properties of (1-x)Pb (ZryTi1-y)O3-xSm(Fe3+0.5,Nb5+0.5)O3(PZT–SFN) (with x = 2 %, 41%≤ y ≤57 %) piezoelectric ceramics were prepared by the conventional solid state method, and effects of SFN and the Zr/Ti ratio content on the piezoelectric properties of PZT ceramics were mainly investigated. A stable solid solution has been formed between PZT and SFN, and a morphotropic phase boundary of PZT–SFN ceramics is identified in the range of 51% ≤ y ≤55 %. The Curie temperature of PZT–SFN ceramics decreases with increasing at Zr/Ti ratio content. A higher εrvalue and a lower tanδ value are demonstrated for the PZT–SFN ceramics with y = 53 %. The PZT–SFN ceramics with y = 53 % has an enhanced electrical behavior of kp~ 61.2 %, Qm~ 104, εr~ 566, tanδ ~ 2.02 % and TC~ 370OC. As a result, PZT–SFN ceramics are promising candidate materials for the field of lead piezoelectric materials and piezoelectric device.


2011 ◽  
Vol 01 (04) ◽  
pp. 471-478 ◽  
Author(s):  
HONGLIANG DU ◽  
SHAOBO QU ◽  
ZHUO XU ◽  
XIAOYONG WEI ◽  
WANCHENG ZHOU ◽  
...  

In order to clarify the Na/K ratios dependence of piezoelectric properties, ( K 1-x Na x) NbO 3 ceramics were prepared by conventional solid-state sintering at x = 0.4–0.6 with a smaller compositional interval (0.02 mol). The results demonstrate that the Na/K ratios have obvious effect on piezoelectric and ferroelectric properties of ( K 1-x Na x) NbO 3 ceramics. Piezoelectric and ferroelectric properties show the maximum (d33 = 147 pC/N, kp = 0.40, and Pr = 24 μC/cm2) at x = 0.54, which is not consistent with conventional viewpoint. The reasons should be attributed to the existence of a phase boundary at x = 0.54 mol, which is similar to the morphotropic phase boundary in Pb(Zr,Ti)O3 ceramics.


2004 ◽  
Vol 848 ◽  
Author(s):  
M.L. Foo ◽  
T. Klimczuk ◽  
L. Li ◽  
N.P. Ong ◽  
R.J. Cava ◽  
...  

ABSTRACTThe synthesis of three layer sodium cobalt oxide, NaxCoO2 (x=0.3, 0.5, 0.6, 0.75 and 1.0) is reported. For x=0.6, 0.75, and 1.0, conventional solid-state synthesis was employed. x=0.3 and 0.5 were obtained via oxidative deintercalation of sodium at room temperature. x=0.3 can be hydrated to Na0.3CoO2•1.3H2O which is superconducting with a Tc of 4.3 K. Although having the same chemical stiochiometry as the previously reported two layer superconductor, it has a different stacking sequence of CoO2 layers making it structurally distinct. Crystals of three layer NaCoO2 show triangular morphology compared to hexagonal morphology for two layer Na0.7CoO2.


2019 ◽  
Vol 09 (03) ◽  
pp. 1950022 ◽  
Author(s):  
Zhi-Hao Zhao ◽  
Rui-Fang Ge ◽  
Yejing Dai

This paper investigates a system of 0.93[Formula: see text][Formula: see text]TiO3–0.06BaTiO3–0.01[Formula: see text][Formula: see text]NbO3–[Formula: see text]CuO (BNT–BT–KNN–[Formula: see text]CuO, [Formula: see text][Formula: see text]mol.%) ceramics, which were fabricated by the conventional solid-state process through the granulation of vacuum freeze drier. The results show that the CuO doping made a significant enhancement on the piezoelectric properties of the BNT–BT–KNN ceramics. With the doping of CuO, the transition temperature between ferroelectric phase and ergodic relaxor state is reduced to near room temperature, resulting in pinched [Formula: see text]–[Formula: see text] loops and “sprout” shape [Formula: see text]–[Formula: see text] curves. For the composition with [Formula: see text], a high unipolar strain of 0.39% under 5[Formula: see text]kV/mm contributes a large [Formula: see text][Formula: see text]pm/V at room temperature, which is competitive with the other BNT-based ceramics.


2013 ◽  
Vol 634-638 ◽  
pp. 2345-2348 ◽  
Author(s):  
Hong Mei Zhang ◽  
Shao Bo Qu ◽  
Jing Bo Zhao ◽  
Hong Liang Du

(1-X)K0.5Na0.5NbO3–xBiGaO3[(1-X)KNN-Xbg] Lead-Free Ceramics with Different Additive of Bigao3 Were Synthesized by Conventional Solid-State Sintering Technique. Dielectric, Piezoelectric and Ferroelectric Properties of (1-X)KNN-Xbg Lead-Free Ceramics Were Studied. it Is Found that the Piezoelectric Properties Was Improved due to the Additive Bigao3,The Ceramics X=0.01 near Room Temperature Exhibit Excellent Electrical Properties D33=152pC/N, TC=372 °C. these Results Indicate that Bigao3 Adjusted K0.5Na0.5NbO3-Based Ceramics Materials Are Promising Lead-Free Piezoelectric Ceramic Candidates for Practical Applications.


1998 ◽  
Vol 278-281 ◽  
pp. 379-383 ◽  
Author(s):  
Federica Bondioli ◽  
A. Bonamartini Corradi ◽  
Anna Maria Ferrari ◽  
Tiziano Manfredini ◽  
Gian Carlo Pellacani

2008 ◽  
Vol 368-372 ◽  
pp. 69-71 ◽  
Author(s):  
Xiang Ping Jiang ◽  
Long Zhu Li ◽  
Fu Lan Jiang ◽  
Yan Yan Zheng ◽  
Li Hua Liu

Lead-free piezoelectric ceramics of (Na0.8K0.2)0.5Bi0.5TiO3+x wt.% Mn (abbreviated as NBKT-x% Mn, x=0~0.5) were synthesized by solid-state reaction. The grain growth of the ceramics was restrained by Mn-doping at a certain extent. The mechanical quality factor Qm increases and the dielectric loss tanδ decreases with the increase of Mn-doping. Best piezoelectric properties were obtained for the composition of NKBT-0.2%Mn: d33=158 pC·N-1, tanδ=2.9% at 1 kHz, Qm=110 and kp=30%. The P-E loops show that remnant polarization Pr and coercive field Ec decrease slightly with the amount of the Mn2+ increasing up to 0.2wt.% and then increase as the content of Mn2+ increases further. NKBT-0.5wt. % Mn exhibits strong ferroelectricity with remnant polarization Pr = 38μC/cm2.


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