• Title/Summary/Keyword: $Bi_{0.5}K_{0.5}TiO_3$

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Electrocaloric Effect of [Bi0.5(Na0.84K0.16)0.5]TiO3 Lead-free Ceramics ([Bi0.5(Na0.84K0.16)0.5]TiO3 무연 세라믹스의 전기열량 효과)

  • Han, Jong-Dae;Yoo, Ju-Hyun;Jeong, Yeong-Ho
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
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    • v.28 no.4
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    • pp.234-237
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    • 2015
  • In this work, in order to develop the ceramics with an excellent electrocaloric effect, $[Bi_{0.5}(Na_{0.84}K_{0.16})_{0.5}]TiO_3$ ceramics were fabricated by conventional solid state reaction method. The ceramics was observed as rhombohedral phase by X-ray diffraction patterns. To investigate the electrocaloric effect of the ceramics, P-E hysteresis loops were measured at various temperature. The temperature change ${\Delta}T$ of these ceramics was calculated using the Maxwell's relations. The maximum value of temperature change ${\Delta}T$ was obtained as 0.3 $1^{\circ}C$ at $165^{\circ}C$ under applied electric fields 45 kV/cm.

Optimum Compositions for Piezoelectric Properties of Pb-free (Bi0.5Na0.5)(1-x)BaxTiO3 Ceramics (비납계 (Bi0.5Na0.5)(1-x)BaxTiO3 압전 세라믹 재료의 최적 조성)

  • Sung, Yeon-Soo;Yeo, Hong-Goo;Cho, Jong-Ho;Song, Tae-Kwon;Jeong, Soon-Jong;Song, Jae-Sung;Kim, Myong-Ho
    • Korean Journal of Materials Research
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    • v.17 no.2
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    • pp.68-72
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    • 2007
  • Optimum compositions for piezoelectric properties of $(Bi_{0.5}Na_{0.5})_{(1-x)}Ba_xTiO_3$ ceramics were investigated in the range of $x=0{\sim}0.1$ covering rhombohedral to tetragonal phase regions. No impurity phases other than a perovskite phase were found and the grain size decreased with increasing x. A two-phase coexisting morphotropic phase area rather than boundary dividing rhombohedral and tetragonal phase regions appeared to exist at $x=0.05{\sim}0.08$. As for piezoelectric properties within morphotropic phase compositions, the piezoelectric constant ($d_{33}$) and the electromechanical coupling factor ($K_p$) showed peak values at x=0.065, 192 pC/N and 34%, respectively, indicating x=0.065 as an optimum composition for piezoelectric $(Bi_{0.5}Na_{0.5})_{(1-x)}Ba_xTiO_3$ ceramics.

Dielectric properties of ($Sr_{0.50}Pb_{0.25}Ba_{0.25}$)$TiO_3$-$Bi_2$$Ti_3$$O_{9}$ ceramics for the high-voltage capacitor (고전압 캐패시터용 ($Sr_{0.50}/$Pb_{0.25}$/$Ba_{0.25}$)$TiO_3$-$Bi_2$$Ti_3O_{9}$ 세라믹의 유전특성)

  • 김세일;정장호;이영희;배선기
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 1993.11a
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    • pp.17-20
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    • 1993
  • In this paper, the (1-x)($Sr_{0.50}$$Pb_{0.25}$$Ba_{0.25}$)$TiO_3$-x $Bi_2$$Ti_3$$O_{9}$(x=0,4,6,8[mol.%]) ceramics with paraelectric properties were, fabricated by mixed oxide method. The dielectric and structural properties of ceramics were studied with sintering temperature and addition of $Bi_2Ti_3O_{9}$, and the application for the high - voltage capacitor was investigated. In the specimens with sintering at 1350[$^{\circ}C$], sintered density was showed the highest value of 5.745[g/cm$^3$]. Increasing of sintering temperature, average grain size was increased. The specimen. ($Sr_{0.50}$$Pb_{0.25}$$Ba_{0.25}$)$TiO_3$sintered at 1350[$^{\circ}C$] showed good dielectric properties and breakdown voltage was showed the highest value of 200[kV]. Temperature coefficient of capacitance was stabilized in specimens added $Bi_2Ti_3O_{9}$ Sintered density. dielectric properties and breakdown voltage ware decreased with increasing the contents of $Bi_2Ti_3O_{9}$.

Effect of Excess CuO on the Sintering Behavior and Piezoelectric Properties of Bi0.5(Na0.82K0.18)0.5TiO3 Ceramics (Bi0.5(Na0.82K0.18)0.5TiO3 세라믹스의 소결거동 및 압전 특성에 대한 과잉의 CuO 첨가 효과)

  • Kang, Jin-Kyu;Jang, Hyun-Deok;Heo, Dae-Jun;Lee, Hyun-Young;Ahn, Kyoung-Kwan;Lee, Jae-Shin
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
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    • v.27 no.6
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    • pp.372-376
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    • 2014
  • We investigated the effect of excess CuO on the sintering behavior, ferroelectric, and piezoelectric properties of lead-free $Bi_{0.5}(Na_{0.82}K_{0.18})_{0.5}TiO_3$ (BNKT) ceramics. The addition of excess CuO was found to greatly contribute to the densification and grain growth, however, excess CuO over 3 mol% was precipitated at grain boundaries after sintering. BNKT with 1~2 mol% CuO in excess sintered at $975^{\circ}C$ showed piezoelectric properties comparable to those of unmodified BNKT sintered at $1,175^{\circ}C$. These results seem meaningful for its application to low cost multilayer actuators (MLAs) because low firing ceramics make it possible to apply less expensive base metals to the inner electrode of MLAs.

Piezoelectric and Ferroelectric Properties of $[Bi_{1-x}(Na_{0.7-x}K_{0.2}Li_{0.1})]_{0.5}Ba_xTiO_3$ Lead-Free Piezoelectric Ceramics (비납계 $[Bi_{1-x}(Na_{0.7-x}K_{0.2}Li_{0.1})]_{0.5}Ba_xTiO_3$ 압전 세라믹의 압전-유전특성)

  • Lee, Dae-Su;Jeong, Soon-Jong;Kim, Min-Su;Park, Eun-Cheol;Song, Jae-Sung
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 2006.06a
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    • pp.271-271
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    • 2006
  • The structural, dielectric and piezoelectric properties of $[Bi_{1-x}(Na_{0.7-x}K_{0.2}Li_{0.1})]_{0.5}BaxTiO_3$ (BNKLBxT) ceramics were studied for the compositional range, x = 0-0.08. The samples were prepared by conventional sintering technique. The result of X-ray diffraction (XRD) suggest that $Ba^{2+}$ diffuse into the $[Bi(Na_{0.7}K_{0.2}Li_{0.1})]_{0.5}TiO_3$ (BNKLT) lattices to form a solid solution with a single phase perovskite structure. The ceramic show excellent piezoelectric and ferroelectric properties, and optimum properties measured are as follows: piezoelectric constant $d_{33}=230pC/N$, planar electromechanical coupling factor $k_p\;=\;40.3%$, remanent polarization $P_r\;=\;30\;{\mu}C/cm^2$, and coercive field $E_c\; =\;2.5\;kV/mm$, respectively.

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Dielectric and Piezoelectric Characteristics of $Bi_{0.5}(Na_{0.84}K_{0.16})_{0.5}TiO_3$ Ceramics with the variations of Sr Substitution (Sr 치환에 따른 $Bi_{0.5}(Na_{0.84}K_{0.16})_{0.5}TiO_3$ 세라믹스의 유전 및 압전특성)

  • Oh, Dong-On;Ryu, Ju-Hyun;Park, Chang-Yub;Yoon, Hyun-Sang;Jeong, Yeong-Ho;Jung, Moon-Young
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 2003.07b
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    • pp.660-663
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    • 2003
  • In this Study, lead-free $Bi_{0.5}(Na_{0.84}K_{0.16})_{0.5}TiO_3$ system ceramics were fabricated with the variations of Sr substitution and their dielectric and piezoelectric characteristics were investigated. With the increase of Sr substitution, dielectric constant increased linearly and Curie temperature decreased slightly. Also, the temperature dependence curve of dielectric constant was moved to left-ward. At 4mol% Sr substitution, Tc of 292, kp of 34.03%, kt of 45.32% and ${\epsilon}r$ of 868 were shown, respectively.

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Piezoelectric Properties of Pb-free Bi(Na,K)TiO3-SrTiO3 Ceramics with the Amount of La2O3 Addition (La2O3첨가에 따른 무연 Bi(Na,K)TiO3-SrTiO3 세라믹스의 압전 특성)

  • 류주현;이현석;박창엽;정광현;이덕출;정영호;홍재일
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
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    • v.17 no.8
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    • pp.830-834
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    • 2004
  • In this study, lead-free pirzoelectric ceramics were investigated for pressure sensor applications as a function of the amount of ${La}_2{O}_3$ addition at $Bi(Na, K)Ti{O}_3-SrTi{O}_3$system. With increasing the amount of addition, the density and dielectric constant increased up to 0.9 wt% ${La}_2{O}_3$ addition and decreased above 0.9 wt% ${La}_2{O}_3$addition. Electromechanical coupling factor( $K_{P}$) showed the maximum value at 0.2 wt% ${La}_2{O}_3$addition and decreased above 0.2 wt% ${La}_2{O}_3$ addition. Electromechanical coupling $factor{(K)}_P$, density, dielectric constant$(\varepsilon_\Gamma)$, piezoelectric constant$(d_33)$ and curie temperature$(T_C)$ showed optimum value of 0.40, 5.75 g/㎤, 768, 215 pC/N and 320 $^{\circ}C$ at 0.2 wt%${La}_2{O}_3$addition, respectively.

Positive Temperature Coefficient of Resistivity(PTCR) Behavior of Nb2O5 Added Ba0.99(Bi0.5Na0.5)0.01TiO3 Ceramics as a Function of Sintering Time (Nb2O5 첨가와 소결시간에 따른 Ba0.99(Bi0.5Na0.5)0.01TiO3 세라믹스의 PTCR 특성)

  • Oh, Young-Kwang;Choi, Seung-Hun;Yoo, Ju-Hyun
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
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    • v.24 no.7
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    • pp.559-562
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    • 2011
  • In this study, the effect of $Nb_2O_5$ and sintering time on the positive temperature of coefficient of resistivity (PTCR) behavior of lead free $Ba_{0.99}(Bi_{0.5}Na_{0.5})_{0.01}TiO_3$ (BBNT) ceramics were investigated in order to fabricate a PTC thermistor with high $T_c$ temperature more than $140^{\circ}C$. In particular, BBNT ceramic doped with 0.1mol% $Nb_2O_5$ and sintered at $1350^{\circ}C$ for 4 h has significantly increased Curie temperature ($T_c$) of about $200^{\circ}C$, showed good PTCR behavior of room-temperature resistivity ($\rho_{rt}$) of $40{\Omega}{\cdot}cm$, a high $\rho_{max}/\rho_{min}$ ratio of $43.78{\times}10^3$ and a large resistivity temperature factor (${\alpha}$) of 16.1%/$^{\circ}C$. With increasing addition of $Nb_2O_5$ content, the $\rho_{rt}$ decreased to a minimum value of $40\;{\Omega}cm$ at 0.1mol% $Nb_2O_5$ and the $\rho_{rt}$ increased for x value over 0.1 mol%.

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
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    • v.25 no.10
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    • pp.566-570
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    • 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.

Dielectric and Piezoelectric Properties of Pb-free Bi(Na, K)TiO3-SrTiO3 Ceramics with MnO2 Addition (MnO2 첨가에 따른 무연 Bi(Na, K)TiO3-SrTiO3 세라믹스의 유전 및 압전 특성)

  • Lee, Mi-Young;Ryu, Sung-Lim;Yoo, Ju-Hyun;Chung, Kwang-Hyun;Jeong, Yeong-Ho;Hong, Jae-Il;Yoon, Hyun-Sang
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
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    • v.17 no.10
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    • pp.1056-1060
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    • 2004
  • In this study, 0.96B $i_{0.5}$($Na_{0.84}$ $K_{0.16}$)$_{0.5}$Ti $O_3$ + 0.04SrTi $O_3$ + 0.3 wt% N $b_2$ $O_{5}$+0.2 wt% L $a_2$ $O_3$ + xwt % Mn $O_2$ were investigated as a function of the amount of Mn $O_2$ addition in order to improve dielectric and piezoelectric properties of Lead-free piezoelectric ceramics. With increasing the amount of Mn $O_2$ addition, the density, electromechanical coupling factor( $k_{p}$), piezoelectric constant( $d_{33}$, $g_{33}$) and curie temperature (Tc) showed the maximum value of 5.7 g/㎤, 38 %, 219 pC/N, 26 mVㆍm/N and 32$0^{\circ}C$ at 0.1 wt% Mn $O_2$ addition, respectively, and mechanical quality factor( $Q_{m}$ ) showed the maximum value of 158 at 0.3 wt% Mn $O_2$ addition.ddition.ion.n.