scholarly journals Structural and Electric Properties of MnO2-Doped KNN-LT Lead-Free Piezoelectric Ceramics

Crystals ◽  
2020 ◽  
Vol 10 (8) ◽  
pp. 705
Author(s):  
Yunfeng Deng ◽  
Junjun Wang ◽  
Chunxiao Zhang ◽  
Hui Ma ◽  
Chungeng Bai ◽  
...  

Structural, ferroelectric, dielectric, and piezoelectric properties of K0.5Na0.5NbO3-LiTaO3-xmol%MnO2 lead-free piezoelectric ceramics with 0.0 ≤ x ≤ 0.3 were studied. The ceramic samples were synthesized through the conventional solid-state reaction method. The MnO2 addition can reduce the sintering temperature of KNLNT ceramics. Compared with undoped KNLNT ceramic, the piezoelectric measurements showed that piezoelectric properties of K0.5Na0.5NbO3-LiTaO3-xMnO2 were improved (d33 = 251 pC/N) when x = 0.1. In addition, KNLNT-xMnO2 ceramics have larger Pr(20.59~21.97 μC/cm2) and smaller Ec(10.77~6.95 kV/cm), which indicates MnO2 has excellent softening property, which improves the ferroelectric properties of KNLNT ceramics This work adds relevant information regarding of potassium sodium niobate K0.5Na0.5NbO3 (KNN) when doped Li, Ta, Mn at the B-site.

2011 ◽  
Vol 328-330 ◽  
pp. 1131-1134
Author(s):  
Qian Chen ◽  
Zhi Jun Xu ◽  
Rui Qing Chu ◽  
Yong Liu ◽  
Ming Li Chen ◽  
...  

Lead-free piezoelectric ceramics Sr2Bi4-xGdxTi5O18 were prepared by conventional solid-state reaction method. Pure bismuth layered structural ceramics with uniform gain size were obtained in all samples. The effect of Gd-doping on the dielectric, ferroelectric and piezoelectric properties of Sr2Bi4Ti5O18 ceramics were also investigated. It was found that that Gd3+ dopant gradually decreased the Curie temperature (Tc) with the lower dielectric loss (tand) of SBTi ceramics. In addition, Gd-doping with appropriate content improved the ferroelectric and piezoelectric properties of the SBTi ceramics. The piezoelectric constant (d33) of the Sr2Bi3.9Gd0.1Ti5O18 ceramic reached the maximum value, which is 22 pC/N. The results showed that the Sr2Bi4-xGdxTi5O18 ceramic was a promising lead-free piezoelectric material.


2014 ◽  
Vol 787 ◽  
pp. 242-246
Author(s):  
Rui Lin Wu ◽  
Tomoaki Karaki ◽  
Jiang Tao Zeng ◽  
Liao Ying Zheng ◽  
Wei Ruan ◽  
...  

Lead-based piezoelectric ceramics have excellent piezoelectric properties with the compositions near the rhombohedral-tetragonal morphotropic phase boundary (MPB)[1,2]. In these materials, the dielectric and piezoelectric properties show the maximal values at MPB. For lead-free piezoelectric ceramics, finding the MPB area is a promising way to improve their properties. In this paper, the (1-x-y)BaZrO3-x(K0.45Na0.5Li0.05)NbO3-yBi (Mg0.5Ti0.5)O3 lead-free piezoelectric ceramics were prepared by solid-state reaction method, and their piezoelectric properties and dielectric properties were investigated. With the increase of KNLN content, the crystal structure changed from rombohedral phase to tetragonal phase, thus existed a MPB[3,4] between rombohedral and tetragonal phase. At room temperature, the specimen with the composition at MPB (x=0.93, y=0.01) shows the optimal piezoelectric properties (d33=225pC/N and kp=45%), which indicates that this material is a potential lead-free piezoceramic.


2012 ◽  
Vol 549 ◽  
pp. 651-654 ◽  
Author(s):  
Zhi Wen Zhu ◽  
Xin You Huang ◽  
Hai Tang Hua ◽  
Yan Li

Ba0.85Ca0.15Ti0.9Zr0.1O3-xLi2CO3 lead-free piezoelectric ceramics (abbreviated as BCZT-xLi) were prepared by conventional solid state reaction method. The microstructure, piezoelectric properties and dielectric properties were studied for BCZT-xLi samples doped with different Li2CO3 content(x= 0, 0.05, 0.1 0.2 0.3, 0.4wt. %). The results show that the piezoelectric constant(d33), planar electron mechanical coupling coefficient(kp) and thickness electron mechanical(kt) of BCZ-T-xLi ceramics increase firstly and decreases subsequently with increasing of Li+ doping amount, the dielectric loss(tanδ) of BCZT-xLi ceramics decreases firstly and then increases at the same time while Li+ doping amount increases. But the r-elative permittivity (εr) of BCZT-xLi ceramics increases all the time. With the in-creasing of the amount of Li2CO3 doped the grain size of BCZT-Li ceramic first increases and then decreases. The BCZT-xLi ceramics display the optimum properties (d33=83, tanδ=0.035, εr=2020, kp=0.41, kt=0.046) while Li2CO3 doped amount is 0.20wt. %.


Crystals ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 555
Author(s):  
Mu Song ◽  
Xiaoyuan Sun ◽  
Qiong Li ◽  
Hao Qian ◽  
Yunfei Liu ◽  
...  

Lead-free piezoelectric ceramics with both low hysteresis and superior electrostrictive coefficient features are crucial toward providing desired performance for intelligent electrical devices, especially in high-precision displacement actuators. In this work, we propose a novel scenario, which is to design the phase transition around ambient temperature to enhance electrostrictive effect and inhibit hysteresis. In other words, the dense ceramics with cubic phases (C) and tetragonal phases (T) coexisting at RT (room temperature) were designed. According to this scenario, the Ba(1−x)SrxTiO3 (abbreviated as BT-100xST) ceramics were fabricated by the conventional solid-state reaction method. The relaxor behavior, ferroelectric properties, crystal structure and microstructure of BT-100xST ceramics have been investigated in detail. As a result, the BT-100xST ceramics with x = 0.20–0.40 present relaxor behavior which was indicated by dielectric constant as a function of temperature and (polarization–electric field) P–E hysteresis loops. The BT-30ST ceramics exhibit enhanced electrostrictive coefficient Q33 (>0.034 m4/C2), and the electrostrictive strain and low hysteresis achieves 0.11% and 2%, respectively. The BT-100xST ceramics are considered as a prospective option for application in displacement actuators with high sensitivity and high precision.


Author(s):  
Nan Wei ◽  
Tomoaki KARAKI ◽  
Tadashi Fujii

Abstract (K,Na,Li)NbO3-BaZrO3-(Bi,Na)TiO3-x B2O3 (abbreviated as KNLN-BZ-BNT-x B2O3) ceramics were prepared by conventional solid state reaction method. The effects of B2O3 content on dielectric and piezoelectric properties of the KNLN-BZ-BNT ceramics have been studied. Based on the identification by X-ray diffraction (XRD), all the samples show a two-phase coexistence zone consisting of rhombohedral (R) and tetragonal (T) phases. For the ceramics with x = 0.5 wt%, the sintering temperature was observed to reduce from 1200 oC to 940 oC, while the samples maintained a high relative density around 97%. Because of the high densification and large grain size, the dielectric and piezoelectric properties were improved. As a result, the ceramics with x = 0.5 wt% sintered at 940 oC exhibited good properties of d 33 = 197 pC/N, k p= 0.29, tan δ = 0.029 and ε r = 1889, together with a Curie temperature (T C) of 222 oC.


2007 ◽  
Vol 42 (9) ◽  
pp. 1594-1601 ◽  
Author(s):  
Hongliang Du ◽  
Fusheng Tang ◽  
Fa Luo ◽  
Dongmei Zhu ◽  
Shaobo Qu ◽  
...  

2018 ◽  
Vol 6 (41) ◽  
pp. 19967-19973 ◽  
Author(s):  
Zhenyong Cen ◽  
Yu Huan ◽  
Wei Feng ◽  
Yan Yu ◽  
Peiyao Zhao ◽  
...  

Lead-free (1 − x)(0.96K0.46Na0.54Nb0.98Ta0.02O3–0.04Bi0.5(Na0.82K0.18)0.5ZrO3)–xCaZrO3 ((1 − x)(0.96KNNT–0.04BNKZ)–xCZ) piezoelectric ceramics were prepared by the conventional solid-state reaction method.


2011 ◽  
Vol 492 ◽  
pp. 194-197 ◽  
Author(s):  
Yue Fang Wang ◽  
Xiu Jie Yi ◽  
Wei Pan ◽  
Guo Zhong Zang ◽  
Juan Du

Lead-free (1-x-y)Na1/2Bi1/2TiO3-xBaTiO3-yBiFeO3 ceramics were synthesized by ordinary sintering technique. The compositional dependence of phase structure and electrical properties of the ceramics was systematically investigated. All samples possessed pure perovskite structure. The dielectric and piezoelectric properties of ceramics were investigated with the amount of different BiFeO3 substitutions. The addition of BiFeO3 can not only decrease Ec and Pr but also lead to a significant degradation of the dielectric loss tanδ.


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