• Title, Summary, Keyword: Lead-free piezoelectric ceramics

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Structural and piezoelectric properties of lead-free (1-x)$(Na_{0.5}\;K_{0.5})NbO_3$-xBa($Ti_{0.9}$, $Sn_{0.1}$)$O_3$ ceramics

  • Cha, Yu-Jeong;Nam, San;Kim, Chang-Il;Jeong, Yeong-Hun;Lee, Yeong-Jin;Baek, Jong-Hu
    • Proceedings of the Materials Research Society of Korea Conference
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    • pp.33.1-33.1
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    • 2009
  • Lead-free (1-x)$(Na_{0.5}K_{0.5})NbO_3$-xBa($Ti_{0.9}Sn_{0.1})O_3$ [NKN-BTS-100x] ceramics doped with 1 mol% $MnO_2$ have been prepared by the conventional solid state method and their structural and piezoelectric properties were investigated. The NKN-BTS-100x ceramics exhibited a dense and homogeneous microstructure when they were sintered at $1030-1150^{\circ}C$. Grain growth was observed for the specimen sintered at relatively low temperature of $1050^{\circ}C$. A tetragonal/orthorhombic morphotropic phase boundary (MPB) in the perovskite structure was also appeared for the NKN-BTS-100x ceramics (0.04$1050^{\circ}C$. The enhanced piezoelectric properties in the NKN-BTS ceramics with a MPB composition were obtained. Especially, for the NKN-BTS-6 ceramics, a high dielectric constant (${\varepsilon}^T_3/\varepsilon_0=1,400$), piezoelectric constant ($d_{33}=237$) and electromechanical coupling factor ($k_p=0.42$) were obtained.

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BiFeO3-based Lead-free Piezoelectric Ceramics (비스무스 페라이트계 무연 압전 세라믹스)

  • Choi, Jin-Hong;Kim, Hyun-Ah;Han, Seung-Ho;Kang, Hyung-Won;Lee, Hyeung-Gyu;Kim, Jeong-Seog;Cheon, Chae-Il
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
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    • v.25 no.9
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    • pp.692-701
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    • 2012
  • Recently, many lead-free piezoelectric materials have been investigated for the replacement of existing Pb-based piezoelectric ceramics because of globally increasing environmental interest. There has been remarkable improvement in piezoelectric properties of some lead-free ceramics such as $(Bi,Na)TiO_3-(Bi,K)TiO_3-BaTiO_3$, $(Na,K)NbO_3-LiSbO_3$, and so on. However, no one still has comparable piezoelectric properties to lead-based materials. Therefore, new lead-free piezoelectric ceramics are required. $BiFeO_3$ has a rhombohedrally distorted perovskite structure at room temperature and a very high Curie temperature ($T_C$= 1,100 K). And a very large electric polarization of 50 ~ 60 ${\mu}C/cm^2$ has been reported both in epitaxial thin film and single crystal $BiFeO_3$. Therefore, a high piezoelectric effect is expected also in a $BiFeO_3$ ceramics. The recent research activities on $BiFeO_3$ or $BiFeO_3$-based solid solutions are reviewed in this article.

Microstructure and Piezoelectric Properties in the (Na,K,Li)(Nb,Sb)$O_3$ system ((Na,K,Li)(Nb,Sb)$O_3$ 세라믹스의 압전특성과 미세조직의 변화)

  • Jeon, So-Hyun;Kim, Min-Soo;Jeong, Soon-Jong;Kim, In-Sung;Min, Bok-Ki;Song, Jae-Sung
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • pp.280-280
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    • 2007
  • Lead oxide-based ferroelectrics are the most widely used materials for piezoelectric actuators, sensors and transducers due to their excellent piezoelectric properties. Considering lead toxicity, there is great interest in developing lead-free piezoelectric materials, which are biocompatible and environmentally friendlier. Recently alkali oxide materials, including sodium - potassium niobate (NKN), have been given attention in view of their ultrasonic application and also as promising candidates for piezoelectric lead-free system. However, it is difficult to sinter such NKN-based materials via conventional sintering process. In this reason, many researchers have investigated hot press, hot isostatic press or spark-plasma sintering of NKN-based ceramics. In this study, as candidates for lead-free piezoelectric materials, dense (Na,K,Li)(Nb,Sb)$O_3$ systems were developed by conventional sintering process. The microstructures and piezoelectric properties of the (Na,K,Li)(Nb,Sb)$O_3$ systems were investigated as a function of variable compositions. The excellent piezoelectric and electromechanical properties indicate that this system is potentially good candidate as lead-free material for a wide range of electro-mechanical transducer applications.

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Piezoelectric Properties of Lead-Free $(Na_xK_{0.94-x}Li_{0.06})NbO_3$ Ceramics ($(Na_xK_{0.94-x}Li_{0.06})NbO_3$ 세라믹스의 압전 및 유전 특성)

  • Jeon, So-Hyun;Kim, Min-Soo;Park, Jeong-Joo;Jeong, Soon-Jong;Kim, In-Sung;Song, Jae-Sung
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • pp.276-276
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    • 2007
  • As a candidate for lead-free piezoelectric materials, dense $(Na_xK_{0.94-x}Li_{0.06})NbO_3$ ceramics were developed by conventional sintering process. Sintering temperature was lowered by adding 1 mol% $Li_2O$ as a sintering aid. The electrical properties of $(Na_xK_{0.94-x}Li_{0.06})NbO_3$ ceramics were investigated as a function of Na/K ratio. When the sample sintered at $950^{\circ}C$ for 4 h with the compositions of morphotropic phase boundary, 0.47 < x < 0.51, electro-mechanical coupling factor ($k_p$) and piezoelectric coefficient ($d_{33}$) were found to reach the highest values of 0.42 and 190 pC/N, respectively. These excellent piezoelectric and electro-mechanical properties indicate that this system is potentially good candidate for lead-free material for a wide range of electro-mechanical transducer applications.

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Piezoelectric Properties of NKN-LST Ceramics with ZnO and CuO Addition (ZnO와 CuO 첨가에 따른 NKN-LST 세라믹스의 압전 특성)

  • Lee, Seung-Hwan;Lee, Sung-Gap;Lee, Young-Hie
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
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    • v.24 no.8
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    • pp.632-635
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    • 2011
  • Additions (ZnO, CuO) doped $0.98(Na_{0.5}K_{0.5})NbO_3-0.02Li(Sb_{0.17}Ta_{0.83})O_3$ (0.98NKN-0.02LST-x) lead free piezoelectric ceramics have been fabricated by ordinary sintering technique. The effects of additions doping on the dielectric, piezoelectric, and ferroelectric properties of the ceramics were mainly investigated. X-ray diffraction of the sample appeared orthorhombic phase. The specimen doped with additions exhibits enhanced electrical properties ($d_{33}$= 153 pC/N). These results indicate that the 0.98NKN-0.02LST-x ceramics is a promising candidate for lead-free piezoelectric ceramics for applications such as piezoelectric actuators, harmonic oscillator and so on.

Piezoelectric and Dielectric Properties of Low Temperature Sintering (Na,K,Li)(Nb,Sb,Ta)O3 Ceramics Doped with CuO (CuO 첨가된 저온소결 (Na,K,Li)(Nb,Sb,Ta)O3계 세라믹스의 압전 및 유전 특성)

  • Lee, Gwang-Min;Yoo, Ju-Hyun;Lee, Jie-Young
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
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    • v.28 no.4
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    • pp.229-233
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    • 2015
  • In this paper, in order to develop outstanding Pb-free piezoelectric composition ceramics, the $(Na_{0.525}K_{0.443}Li_{0.037})(Nb_{0.883}Sb_{0.08}Ta_{0.037})O_3+0.3wt%Bi_2O_3+0.4wt%Fe_2O_3+xwt%CuO$ (x= 0~0.8 wt%)(abbreviated as NKL-NST) lead-free piezoelectric ceramics have been synthesized using the ordinary solid state reaction method. The effects of CuO-doping on the structure and electrical properties of the NKL-NST ceramics were systematically studied. The results show that the ceramics exhibit a pure perovskite structure with orthorhombic phase at room temperature, and secondary phase was found in the ceramics. The 0.4 wt%CuO added ceramics sintered at $950^{\circ}C$ showed the optimum properties of piezoelectric constant($d_{33}$), planar piezoelectric coupling coefficient(kp) and mechanical quality factor(Qm) : $d_{33}=213$[pC/N], kp= 0.43, Qm= 423,respectively.

Dielectric and Piezoelectric Properties of (Na,K)(Nb,Ta,Sb)O3 Ceramics doped with Nb2O5 (Nb2O5 첨가에 따른 (Na,K)(Nb,Ta,Sb)O3 세라믹스의 유전 및 압전 특성)

  • Byeon, Sun-Min;Yoo, Ju-Hyun
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
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    • v.25 no.11
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    • pp.867-872
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    • 2012
  • In this study, in order to develop excellent lead free piezoelectric ceramics for piezoelectric actuators application, $Li_{0.04}(Na_{0.50}K_{0.50})_{0.96}[(Nb_{0.86}Ta_{0.10}Sb_{0.04})_{0.994}Co_{0.015}]O_3+0.0025SrO+0.15\;wt%K_2CO_3+x\;wt%Nb_2O_5$ (x = 0 - 0.5 wt%) (abbreviated as LNKNTSCS-xN) ceramics were fabricated by a conventional sintering technique. the phase structure, microstructure and electrical properties were investigated with a emphasis on the influence of the $Nb_2O_5$ content. High electrical properties of $d_{33}$=234 pC/N, kp=0.392, ${\varepsilon}_r$=1,395, ${\rho}=4.70g/cm^3$ were obtained from the specimen with x=0.4 wt%, which suggests that the composition ceramics is a promising lead-free piezoelectric material.

(K,Na)NbO3-based Lead-free Piezoelectric Materials: An Encounter with Scanning Probe Microscopy

  • Zhang, Mao-Hua;Thong, Hao Cheng;Lu, Yi Xue;Sun, Wei;Li, Jing-Feng;Wang, Ke
    • Journal of the Korean Ceramic Society
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    • v.54 no.4
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    • pp.261-271
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    • 2017
  • Environment-friendly $(K,Na)NbO_3-based$ (KNN) lead-free piezoelectric materials have been studied extensively in the past decade. Significant progress has been made in this field, manifesting competitive piezoelectric performance with that of lead-based, for specific application scenarios. Further understanding of the relationship between high piezoelectricity and microstructure or more precisely, ferroelectric domain structure, domain wall pinning effect, domain wall conduction and local polarization switching underpins the continuous advancement of piezoelectric properties, with the help of piezoresponse force microscopy (PFM). In this review, we will present the fundamentals of scanning probe microscopy (SPM) and its cardinal derivative in piezoelectric and ferroelectric world, PFM. Some representative operational modes and a variety of recent applications in KNN-based piezoelectric materials are presented. We expect that PFM and its combination with some newly developed technology will continue to provide great insight into piezoelectric materials and structures, and will play a valuable role in promoting the performance to a new level.

Piezoelectric properties of lead-free NKNLTS ceramics with $Bi_2O_3$ addition ($Bi_2O_3$첨가에 따른 무연 NKNLTS계 세라믹스의 압전특성)

  • Lee, Youn-Ki;Lee, Eun-Hee;Woo, Duck-Hyun;Ahn, Sang-Ki;Kwon, Soon-Yong;Ryu, Sung-Lim
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • pp.184-184
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    • 2009
  • Lead-free Piezoelectric $[Li_{0.04}(Na_{0.44}K_{0.56})](Nb_{0.88}Ta_{0.1}Sb_{0.02})$ (abbreviated as NKNLTS) has been synthsized by conventional mixed oxide method traditional ceramics process without cold-isostatic pressing. Effect of $Bi_2O_3$ addition on NKNLTS ceramics was investigated. Piezoelectric properties of the ceramic were varied with the amount of $Bi_2O_3$ addition and showed the maximum Kp value at 0.4wt% $Bi_2O_3$ addition. The results show that the optimum poling condition for NKNLTS ceramics of 3.5kV/mm, poling temperature of $120^{\circ}C$ and poling time of 30min. At the sintering temperature of $1100^{\circ}C$ and the calcination temperature $800^{\circ}C$, the optimal values of density=$4.7g/cm^2$, Kp=0.44, $\varepsilon_r$=1309 were obtained. Consequently, lead free piezoelectric ceramics with the excellent piezoelectric could be fabricated using a conventional mixed oxide process and the optimal manuacturing condition of those was obtained.

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Piezoelectric and Dielectric Properties of (Na,K,Li)(Nb,Sb,Ta)O3 Ceramics as a Function of Fe2O3 Addition (Fe2O3첨가에 따른 (Na,K,Li)(Nb,Sb,Ta)O3계 세라믹스의 압전 및 유전 특성)

  • Lee, Gwang-Min;Shin, Sang-Hoon;Yoo, Ju-Hyun
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
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    • v.27 no.9
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    • pp.555-560
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    • 2014
  • In this paper, in order to develop outstanding Pb-free composition ceramics, the $Fe_2O_3$-doped ($Na_{0.525}K_{0.443}Li_{0.037}$)($Nb_{0.883}Sb_{0.08}Ta_{0.037}$)$O_3$ + 0.3 wt% $Bi_2O_3$ + x wt% $Fe_2O_3$ (x= 0~1.0 wt%)(abbreviated as NKL-NST) lead-free piezoelectric ceramics have been synthesized using the ordinary solid state reaction method. The effect of $Fe_2O_3$-doping on their microstructure and electrical properties were investigated. XRD diffraction pattern studies confirm that $Fe_2O_3$ completely diffused into the NKL-NST lattice to form a new stable soild solution with $Fe^{3+}$ entering the $Nb^{5+}$, $Sb^{5+}$ and $Ta^{5+}$ of B-site. And, phase structure of all the ceramics exhibited pure perovskite phase and no secondary phase was found in the ceramics. The ceramics doped with 0.6 wt% $Fe_2O_3$ have the optimum values of piezoelectric constant($d_{33}$), planar piezoelectric coupling coefficient($k_p$) and mechanical quality factor($Q_m$) : $d_{33}$ = 233 [pC/N], $k_p$= 0.44, $Q_m$= 95. These results indicate that the ($Na_{0.525}K_{0.443}Li_{0.037}$)($Nb_{0.883}Sb_{0.08}Ta_{0.037}$)$O_3$ +0.3 wt% $Bi_2O_3$ + 0.6 wt% $Fe_2O_3$ ceramic is a promising candidate for lead-free piezoelectric ceramics.