• Title, Summary, Keyword: Lead-free ceramics

Search Result 198, Processing Time 0.029 seconds

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
    • /
    • /
    • pp.33.1-33.1
    • /
    • 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.

  • PDF

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
    • /
    • v.25 no.9
    • /
    • pp.692-701
    • /
    • 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.

Ring-Type Rotary Ultrasonic Motor Using Lead-free Ceramics

  • Hong, Chang-Hyo;Han, Hyoung-Su;Lee, Jae-Shin;Wang, Ke;Yao, Fang-Zhou;Li, Jing-Feng;Gwon, Jung-Ho;Quyet, Nguyen Van;Jung, Jin-Kyung;Jo, Wook
    • Journal of Sensor Science and Technology
    • /
    • v.24 no.4
    • /
    • pp.228-231
    • /
    • 2015
  • Ultrasonic motors provide high torques and quick responses compared to their magnetic counterparts; therefore, they are widely used in small-scale applications such as mobile phones, microrobots, and auto-focusing modules in digital cameras. To determine the feasibility of lead-free piezoceramics for ultrasonic motor applications, we fabricated a ring-type piezoceramic with a KNN-based lead-free piezoceramic (referred to as CZ5), intended for use in an auto-focusing module of a digital camera. The vibration of the lead-free stator was observed at 45.1 kHz. It is noteworthy that the fully assembled lead-free ultrasonic motor exhibited a revolution speed of 5-7 rpm, even though impedance matching with neighboring components was not considered. This result suggests that the tested KNN-based piezoceramic has great potential for use in ultrasonic motor applications, requiring minimal modifications to existing lead-based systems.

Structural, Dielectric and Field-Induced Strain Properties of La-Modified Bi1/2Na1/2TiO3-BaTiO3-SrZrO3 Ceramics

  • Hussain, Ali;Maqbool, Adnan;Malik, Rizwan Ahmed;Zaman, Arif;Lee, Jae Hong;Song, Tae Kwon;Lee, Jae Hyun;Kim, Won Jeong;Kim, Myong Ho
    • Korean Journal of Materials Research
    • /
    • v.25 no.10
    • /
    • pp.566-570
    • /
    • 2015
  • $Bi_{0.5}Na_{0.5}TiO_3$ (BNT) based ceramics are considered potential lead-free alternatives for $Pb(Zr,Ti)O_3$(PZT) based ceramics in various applications such as sensors, actuators and transducers. However, BNT-based ceramics have lower electromechanical performance as compared with PZT based ceramics. Therefore, in this work, lead-free bulk $0.99[(Bi_{0.5}Na_{0.5})_{0.935}Ba_{0.065}]_{(1-x)}La_xTiO_3-0.01SrZO_3$ (BNBTLax-SZ, with x = 0, 0.01, 0.02) ceramics were synthesized by a conventional solid state reaction The crystal structure, dielectric response, degree of diffuseness and electric-field-induced strain properties were investigated as a function of different La concentrations. All samples were crystallized into a single phase perovskite structure. The temperature dependent dielectric response of La-modified BNBT-SZ ceramics showed lower dielectric response and improved field-induced strain response. The field induced strain increased from 0.17%_for pure BNBT-SZ to 0.38 % for 1 mol.% La-modified BNBT-SZ ceramics at an applied electric field of 6 kV/mm. These results show that La-modified BNBT-SZ ceramic system is expected to be a new candidate material for lead-free electronic devices.

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
    • /
    • /
    • pp.276-276
    • /
    • 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.

  • PDF

Piezoelectric Properties of NKN-BZT Ceramics Sintered with CuO and ZnO Additives (CuO와 ZnO 첨가에 따른 NKN-BZT 세라믹스의 압전 특성)

  • Lee, Seung-Hwan;Baek, Sang-Don;Lee, Dong-Hyun;Lee, Sung-Gap;Lee, Young-Hie
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
    • /
    • v.24 no.8
    • /
    • pp.636-640
    • /
    • 2011
  • The lead-free $0.98(Na_{0.5},K_{0.5})NbO_3-0.02Ba(Zr_{0.52},Ti_{0.48})O_3$-(hereafter NKN-BZT) CuO, ZnO-doped ceramics were prepared using a conventional mixed oxide method. NKN-BZT ceramics doped CuO, ZnO have superior structural and electrical properties than pure NKN-BZT ceramics. For the NKN-BZT-ZnO ceramics sintered at $1,120^{\circ}C$, piezoelectric constant ($d_{33}$) of sample showed the optimum values of 172 pC/N. The $0.98(Na_{0.5},K_{0.5})NbO_3-0.02Ba(Zr_{0.52},Ti_{0.48})O_3$-ZnO ceramics are a promising candidate for lead-free piezoelectric materials.

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
    • /
    • /
    • pp.184-184
    • /
    • 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.

  • PDF

Fabrication and Characteristic of AE sensor using the Lead-free NKN Ceramics (무연 NKN 세라믹스를 이용한 AE 센서 제작 및 특성)

  • Lee, Kab-Soo;Yoo, Ju-Hyun;Hong, Jae-Il
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
    • /
    • /
    • pp.39-40
    • /
    • 2006
  • AE sensor using lead-free ceramics should be developed for prohibiting environment protection. In this study, Langevin type AE sensor was manufactured as air backing structure. Here, the piezoelectic element was used as PZT(EC-65) and NKN, respectively. The resonant frequency of AE sensor using PZT was 143 kHz and the resonant frequency of AE sensor using NKN was 178 kHz. The waveform of AE sensor using NKN was responded more sensitively than that of AE sensor using PZT.

  • PDF

Sensitivity Characteristics of Acoustic Emission(AE) Sensor using the Lead-free (Na1,K)NbO3 Ceramics (무연 (Na1,K)NbO3 계 세라믹스를 이용한 AE센서의 감도특성)

  • Yoo, Ju-Hyun;Lee, Gab-Soo;Hong, Jae-Il
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
    • /
    • v.20 no.3
    • /
    • pp.218-222
    • /
    • 2007
  • In this study, Acoustic emission(AE) sensors were fabricated using lead-free piezoelectric ceramics for prohibiting environmental pollution. Structure of AE sensors were designed as Langvin type air backing form. Here, the piezoelectic element was used as PZT(EC-65)(AE1) and NKN(AE2), respectively. The measured resonant frequency, the maximum sensitivity frequency and sensitivity of AE sensors were as follows ; 143 kHz, 29.4 kHz and 69.3 dB in AE1 and 179 kHz, 29.4 kHz and 66.3dB in AE2, respectively.

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
    • /
    • v.24 no.8
    • /
    • pp.632-635
    • /
    • 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.