• Title, Summary, Keyword: NKN

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Electrical properties of NKN-0.94BNT-0.06BT ceramics (NKN-0.94BNT-0.06BT 세라믹스의 전기적특성)

  • Lee, Young-Hie;Nam, Sung-Pill;Lee, Sung-Gap;Bae, Seon-Gi;Lee, Seung-Hwan
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • pp.298-298
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    • 2010
  • In this study, both structural, dielectric properties of the NKN-0.94BNT-0.06BT ceramics were investigated. All samples of the NKN-0.94BNT-0.06BT ceramics were fabricated by conventional mixed oxide method with Pt electrodes. We report the improved electrical properties in the perovskite structure composed of the NKN, BNT and the BT ceramics. We investigated the effects of NKN, BT on the structural and electrical properties of the NKN-0.94BNT-0.06BT ceramics. The dielectric and structural properties of the NKN-0.94BNT-0.06BT ceramics were superior to those of single composition NKN, NKN-BNT and those values for the NKN-0.94BNT-0.06BT ceramics were 1455, 0.025 and $29.04{\mu}C/cm^2$.

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소결 온도에 따른 비납계 NKN-BNT-BT 세라믹의 전기적, 구조적 특성

  • Lee, Seong-Gap;Nam, Seong-Pil;No, Hyeon-Ji;Bae, Seon-Gi;Lee, Yeong-Hui
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • pp.104-104
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    • 2009
  • In this study, both structural, dielectric and piezoelectric properties of the NKN-0.96BNT-0.04BT ceramics were investigated. All samples of the NKN-0.96BNT-0.04BT ceramics were fabricated by conventional mixed oxide method with Pt electrodes. We report the improved dielectric and piezoelectric properties in the perovskite structure composed of the NKN, BNT and the BT ceramics. We investigated the effects of NKN, BT on the structural and electrical properties of the NKN-0.93BNT-0.07BT ceramics. The dielectric properties and piezoelectric properties of the NKN-0.93BNT-0.07BT ceramics were superior to those of single composition NKN, NKN-BNT and those values for the NKN-0.93BNT-0.07BT ceramics were 861 and 1.12%.

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Polymorphic Phase Transition and Temperature Coefficient of Capacitance of Alkaline Niobate Based Ceramics

  • Bae, Seon-Gi;Shin, Hyea-Gyiung;Sohn, Eun-Young;Im, In-Ho
    • Transactions on Electrical and Electronic Materials
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    • v.14 no.2
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    • pp.78-81
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    • 2013
  • $0.95(Na_{0.5}K_{0.5})NbO_3-0.05BaTiO_3+0.2wt%\;Ag_2O$ (hereafter, No excess NKN) ceramics and $0.95(Na_{0.5}K_{0.5})NbO_3-0.05BaTiO_3+0.2wt%\;Ag_2O$ with excess $(Na_{0.5}K_{0.5})NbO_3$ (hereafter, Excess NKN) were fabricated by the conventional solid state sintering method, and their phase transition properties and dielectric properties were investigated. The crystalline structure of No excess NKN ceramics and Excess NKN ceramics were shown characteristics of polymorphic phase transition (hereafter, PPT), especially shift from the orthorhombic to tetragonal phase by increasing sintering temperature range from $1,100^{\circ}C$ to $1,200^{\circ}C$. Also, the temperature coefficient of capacitance (hereafter, TCC) of No excess NKN ceramics and Excess NKN ceramics from $-40^{\circ}C$ to $100^{\circ}C$ was measured to evaluate temperature stability for applications in cold regions. The TCC of No excess NKN and Excess NKN ceramics showed positive TCC characteristics at a temperature range from $-40^{\circ}C$ to $100^{\circ}C$. Especially, Excess NKN showed a smaller TCC gradient than those of Excess NKN ceramics in range from $-40^{\circ}C$ to $100^{\circ}C$. Therefore, NKN piezoelectric ceramics combined with temperature compensated capacitor having negative temperature characteristics is desired for usage in cold regions.

Ferroelectric properties of NKN Thin Films prepared by Metal Organic Decomposition method (유기금속열분해 방법으로 제작된 NKN 박막의 강유전특성)

  • Kim, Kyoung-Tae;Kim, Chang-Il;Lee, Sung-Gap
    • Proceedings of the KIEE Conference
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    • pp.1394-1395
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    • 2006
  • $(Na_{0.5}LaK_{0.5})NbO_3$ (NKN) thin films were fabricated by the alkoxide-based MOD method. NKN stock solutions were made spin-coated onto the Pt/Ti/$SiO_2$/Si substrate. The structural properties of the NKN thin films examined by x-ray diffraction. The perovskite phase was obtained as a function of the annealing temperature from $550^{\circ}C$ to $700^{\circ}C$ for 1h. The crystallinity and grain size of the NKN thin films increased with increasing annealing temperature. The dielectric constants and loss of the NKN thin films annealed at $650^{\circ}C$ ($t_{eq}$=2.35 nm) showed 323 and 0.025.

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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
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    • pp.39-40
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    • 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.

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Piezoelectric properties of NKN-BT ceramics with various sintering temperature (소결 온도에 따른 NKN-BT 세라믹스의 압전 특성)

  • Jo, Seo-Hyeon;Nam, Sung-Pill;Noh, Hyun-Ji;Kim, Dae-Yeong;Lee, Tae-Ho;Lee, Sung-Gap;Bae, Seon-Gi
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • pp.294-294
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    • 2010
  • In this study, piezoelectric properties of NKN-BT ceramics with various sintering temperature were investigated. The NKN-BT ceramics were fabricated by physicochemical method and characterized by X-ray diffraction analysis and scanning electron microscopy. The structural and dielectric properties of doped BT solution on the NKN ceramics were investigated. The dielectric constant and dielectric loss of NKN-BT ceramics sintered at $1130^{\circ}C$ was 2321 and 0.35, respectively.

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Comparison of Abnormal Grain Growth Behavior of Lead-Free (Na,K)NbO3-M(Cu,Nb)O3, (M = Ca, Sr, Ba) Piezoelectric Ceramics (비납계 (Na,K)NbO3-M(Cu,Nb)O3, (M = Ca, Sr, Ba) 압전 세라믹의 비정상 결정 성장 거동 비교)

  • Jung, Seungwoon;Lim, Ji-Ho;Jung, Han-Bo;Ji, Sung-Yub;Choi, Seunggon;Jeong, Dae-Yong
    • Korean Journal of Materials Research
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    • v.30 no.7
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    • pp.343-349
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    • 2020
  • NKN [(Na,K)NbO3] is a candidate lead-free piezoelectric material to replace PZT [Pb(Zr,Ti)O3]. A single crystal has excellent piezoelectric-properties and its properties are dependent of the crystal orientation direction. However, it is hard to fabricate a single crystal with stoichiometrically stable composition due to volatilization of sodium during the growth process. To solve this problem, a solid solution composition is designed (Na,K)NbO3-Ba(Cu,Nb)O3 and solid state grain growth is studied for a sizable single crystal. Ceramic powders of (Na,K)NbO3-M(Cu,Nb)O3 (M = Ca, Sr, Ba) are synthesized and grain growth behavior is investigated for different temperatures and times. Average normal grain sizes of individual specimens, which are heat-treated at 1,125 ℃ for 10 h, are 6.9, 2.8, and 1.6 ㎛ for M = Ca, Sr, and Ba, respectively. Depending on M, the distortion of NKN structure can be altered. XRD results show that (NKN-CaCuN: shrunken orthorhombic; NKN-SrCuN: orthorhombic; NKN-BaCuN: cubic). For the sample heat-treated at 1,125 ℃ for 10 h, the maximum grain sizes of individual specimens are measured as 40, 5, and 4,000 ㎛ for M = Ca, Sr, and Ba, respectively. This abnormal grain size is related to the partial melting temperature (NKN-CaCuN: 960 ℃; NKN-SrCuN: 971 ℃; NKN-BaCuN: 945 ℃).

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
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    • v.24 no.8
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    • pp.636-640
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    • 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 and Dielectric Properties of NKN-(1-x)BNT-xBT Ceramics (NKN-(1-x)BNT-xBT 세라믹스의 압전 및 유전특성)

  • Lee, Seung-Hwan;Nam, Sung-Pill;Lee, Sung-Gap;Lee, Young-Hie
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
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    • v.23 no.10
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    • pp.771-775
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    • 2010
  • In this study, piezoelectric and dielectric properties of the $(Na_{0.5}K_{0.5})NbO_3-(1-x)(Bi_{0.5}Na_{0.5})TiO_3-xBaTiO_3$ [NKN-(1-x)BNT-xBT] ceramics were investigated. The lead-free NKN-(1-x)BNT-xBT ceramics were fabricated by a conventional mixed oxide method. The results indicate that the addition of $BaTiO_3$ significantly influences the sintering, microstructure, phase transition and electrical properties of NKN-BNT ceramics. A gradual change in the piezoelectric and dielectric properties was observed with the increase of BT contents. The dielectric constant, piezoelectric constant ($d_{33}$) and electromechanical coupling factor ($k_p$) increased at the morphotropic phase boundary (MPB). The $d_{33}$=184 pC/N, $k_p$=0.38, dielectric constant=1455 with dielectric loss value of less than 1% were obtained for the NKN-0.95BNT-0.05BT ceramics sintered at $1150^{\circ}C$ for 2h. These results demonstrate that the NKN-(1-x)BNT-xBT ceramics is an attractive candidate for lead-free piezoelectric materials.

Electrical Properties of Lead Free (1-x)(Na0.5K0.5) NbO3-xLiNbO3 Piezoelectric Ceramics

  • Park, Jong-Ho;Park, Hui-Jin;Choi, Byung-Chun
    • Korean Journal of Materials Research
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    • v.26 no.12
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    • pp.721-725
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    • 2016
  • This work focuses on the electrical conduction mechanism in a lead free ($Na_{0.5}K_{0.5}NbO_3$ ; NKN) ceramics system with $LiNbO_3$ content of approximately critical concentration $x{\geq}0.2$. Lead free $(1-x)(Na_{0.5}K_{0.5})NbO_3-x(LiNbO_3)$, $NKN-LN_x$ (x = 0.1, 0.2) ceramics were synthesized by solid-state reaction method. Crystal structures are confirmed by X-ray diffraction. The electric-mechanical bond coefficient $k_p$ decreases and the phase transition temperature $T_c$ increases with increasing x content, as determined by dielectric and piezoelectric measurements. The value of the real dielectric constants ${\varepsilon}^{\prime}$ and $k_BT{\varepsilon}^{\prime\prime}$ showed anomalies around $T_c$ ($462^{\circ}C$ in the NKN-LN0.1 and $500^{\circ}C$ in the NKN-LN0.2). For the ionic conduction of mobile ions, the activation energies are obtained as $E_I=1.76eV$ (NKN-LN0.1) and $E_I=1.55eV$ (NKN-LN0.2), above $T_c$, and $E_{II}=0.78$ (NKNL-N0.1) and $E_{II}=0.81$ (NKN-LN0.2) below $T_c$. It is believed that the conduction mechanisms of NKN-LNx ceramics are related to ionic hopping conduction, which may arise mainly due to the jumping of $Li^+$ ions.