• 제목/요약/키워드: $Bi_{0.5}K_{0.5}TiO_3$

검색결과 158건 처리시간 0.04초

Preparation of Textured Bi0.5(Na,K)0.5TiO3-BiFeO3 Solid Solutions by Reactive-Templated Grain Growth Process

  • Kato, Kyoko;Kimura, Toshio
    • 한국세라믹학회지
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    • 제43권11호
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    • pp.693-699
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    • 2006
  • Textured $Bi_{0.5}(Na,K)_{0.5}TiO_3-BiFeO_3$ ceramics were prepared by the reactive-templated grain growth process, using platelike $Bi_4Ti_3O_{12}$ particles. The effects of chemical composition in $Bi_{0.5}(Na,K)_{0.5}TiO_3$ on texture development and densification were examined. Textured ceramics were obtained by using $Bi_{0.5}K_{0.5}TiO_3$ as an end member of the solid solution but densification was limited. Dense ceramics were obtained by using $Bi_{0.5}Na_{0.5}TiO_3$ but texture did not develop. Dense, textured ceramics were obtained by using $Bi_{0.5}(Na_{0.5}K_{0.5})_{0.5}TiO_3$.

BiTiO3 첨가에 따른 (Na0.5K0.5)NbO3 세라믹스의 구조적, 전기적 특성 (Structural and Electrical Properties of (Na0.5K0.5)NbO3 Ceramics with Addition of BiTiO3)

  • 이태호;김대영;조서현;정광호;이성갑
    • 전기학회논문지
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    • 제60권11호
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    • pp.2093-2096
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    • 2011
  • In this study, lead-free $(Na_{0.5}K_{0.5})NbO_3-BiTiO_3$ ceramics were fabricated by a conventional mixed oxide method. Structural and electrical properties of lead-free $(Na_{0.5}K_{0.5})NbO_3$ ceramics with the variation of $BiTiO_3$ were investigated. The results of X-ray diffraction analysis showed a typical polycrystalline perovskite structure without presence of the second phase in all specimens. Sintered density increased with an increasing of BTO and the specimen added with 0.07 mol% of $BiTiO_3$ showed the maximum value of 97.8%. Average grain size decreased and densification increased with an increasing of $BiTiO_3$ contents. The electromechanical coupling factor of the 0.01 mol% $BiTiO_3$ doped NKN specimens was 0.32. Dielectric constant, dielectric loss and Curie temperature of the 0.07 mol% $BiTiO_3$ doped NKN specimens were 1185, 0.145% and $400^{\circ}C$, respectively.

무연 BaTiO3-(Bi0.5K0.5)TiO3 PTCR 세라믹과 PTCR 특성에 미치는 Nb2O5의 효과 (Lead-free BaTiO3-(Bi0.5K0.5)TiO3 PTCR Ceramics and Effects of Nb2O5 on Its PTCR Characteristics)

  • 정영훈;박용준;이미재;이영진;백종후;최진수;이우영
    • 한국재료학회지
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    • 제18권9호
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    • pp.475-481
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    • 2008
  • Positive temperature coefficient of resistivity (PTCR) characteristics of (1-x)$BaTiO_3-x(Bi_{0.5}K_{0.5})TiO_3$ ceramics doped with $Nb_2O_5$ were investigated in order to develop the Pb-free PTC thermistor available at high temperatures of > $120^{\circ}C$. The PTCR characteristics appearing in the ($B_{i0.5}K_{i0.5})TiO_3$ (< 5 mol%) incorporated $BaTiO_3$ ceramics, which might be mainly due to $Bi^{+3}$ ions substituting for $Ba^{+2}$ sites. The 0.99$BaTiO_3-0.01(Bi_{0.5}K_{0.5})TiO_3$ ceramics showed good PTCR characteristics of a low resistivity at room temperature (${\rho}_r$) of $31{\Omega}{\cdot}cm$ a high ${\rho}_{max}/{\rho}_{min}$ ratio of $5.38{\times}10^3$, and a high resistivity temperature factor (${\alpha}$) of $17.8%/^{\circ}C$. The addition of $Nb_2O_5$ to 0.99$BaTiO_3-0.01(Bi_{0.5}K_{0.5})TiO_3$ ceramics further improved the PTCR characteristics. Especially, 0.025 mol% $Nb_2O_5$ doped 0.99$BaTiO_3-0.01(Bi_{0.5}K_{0.5})TiO_3$ ceramics exhibited a significantly increased ${\rho}_{max}/{\rho}_{min}$ ratio of $8.7{\times}10^3$ and a high ${\alpha}$ of $18.6%/^{\circ}C$, along with a high $T_c$ of $148^{\circ}C$ despite a slightly increased ${\rho}_r$ of $31{\Omega}{\cdot}cm$.

BiTiO3 첨가에 따른 (Na0.5K0.5)NbO3 세라믹스의 구조적 전기적 특성 (Structural and Electrical Properties of $(Na_{0.5}K_{0.5})NbO_3$ ceramics addition with $BiTiO_3$)

  • 이태호;김대영;조서현;정광호;이성갑;남성필;김영곤
    • 대한전기학회:학술대회논문집
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    • 대한전기학회 2011년도 제42회 하계학술대회
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    • pp.1465-1466
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    • 2011
  • We have studied structural and electrical properties of $(Na_{0.5}K_{0.5})NbO_3$ ceramics addition with $BiTiO_3$. The $(Na_{0.5}K_{0.5})NbO_3-BiTiO_3$ ceramics were fabricated by the conventional mixed oxide method, their dielectric and piezoelectric properties were investigated with the variations of additvie amount $BiTiO_3$. At the sintering temperature of $1130^{\circ}C$, the density, dielectric constant, grain size of 0.05mol% $BiTiO_3$ specimen showed the values of 4.69 g/$cm^3$, 898 and $24.8{\mu}m$.

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$Bi2O_3$ 첨가량 및 소결온도에 따른$(Bi_xBa_{0.6-x}Sr_{0.4})TiO_3$[BBST] 세라믹스의 구조적 특성 (The structural properties of the $(Bi_xBa_{0.6-x}Sr_{0.4})TiO_3$[BBST] ceramics with the sintering temperature and addition of $Bi2O_3$)

  • 남성필;이상철;임성수;이성갑;이영희
    • 대한전기학회:학술대회논문집
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    • 대한전기학회 2002년도 추계학술대회 논문집 전기물성,응용부문
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    • pp.85-87
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    • 2002
  • The $(Ba_xBi_{0.6-x}Sr_{0.4})TiO_3$[x=0.1, 0.2, 0.3] ceramics were prepared by conventional mixed oxide method The structural properties of the $(Ba_xBi_{0.6-x}Sr_{0.4})TiO_3$[x=0.1, 0.2, 0.3] ceramics with the sintering temperature($1200^{\circ}C,\;1250^{\circ}C,\;1300^{\circ}C$) were investigated by XRD, SEM, EDS. Increasing the sintering temperature, the intensity of the $Ba_{0.5}Sr_{0.5}TiO_3$ (100), (110), (111), (200), (310) peaks and $SrBi_4Ti_4O_{15}$ (319), (040) peaks were increased. The gram of the $(Bi_{0.2}Ba_{0.4}Sr_{0.4})TiO_3$ ceramics sintered at $1250^{\circ}C$ were fine and uniform. Increasing the sintering temperature. the average gram size of the $(Bi_{0.2}Ba_{0.4}Sr_{0.4})TiO_3$ ceramics were decreased. The density of $(Bi_{0.1}Ba_{0.5}Sr_{0.4})TiO_3$ ceramics sintered at $1250^{\circ}C$ was 5.4524 [$g/cm^2$].

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PTC 써미스터를 위한 $BaTiO_3-(Bi_{1/2}Na_{1/2})TiO_3$ ($BaTiO_3-(Bi_{1/2}Na_{1/2})TiO_3$ system for PTC Thermistor)

  • 박용준;이영진;백종후;김대준;이우영
    • 한국전기전자재료학회:학술대회논문집
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    • 한국전기전자재료학회 2007년도 추계학술대회 논문집
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    • pp.91-92
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    • 2007
  • An anomalous positive temperature coefficient of electrical resistivity (PTCR) was investigated in a ferroelectric lead-free perovskite-type compound $(Bi_{0.5}Na_{0.5})TiO_3$ within $BaTiO_3$-based solid solution ceramics. The effect of $Nb_2O_5$ content on the electrical properties and the microstructure of (1 - x) $BaTiO_3-x\;(Bi_{0.5}Na_{0.5})TiO_3$ (BNT) ceramics made using a conventional mixed oxide process also has been studied. The Curie temperature was obviously increased with the increasing of $(Bi_{0.5}Na_{0.5})TIO_3$ content. The Nb - doped BNT ceramics (x=0.01) display low resistivity values of $10^{1{\circ}}C-10^{2{\circ}}C$ ohm.cm at room temperature and the Curie Temperature of $T_c=160^{\circ}C$.

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A-site Vacancy가 0.97Bi0.5+x(Na0.78K0.22)0.5-3xTiO3-0.03LaFeO3 무연압전 세라믹스의 압전특성에 미치는 영향 (Effects of A-site Vacancies on the Piezoelectric Properties of 0.97Bi0.5+x(Na0.78K0.22)0.5-3xTiO3-0.03LaFeO3 Lead-free Piezoelectric Ceramics)

  • 박정수;이규탁;조정호;정영훈;백종후;윤지선
    • 한국세라믹학회지
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    • 제51권6호
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    • pp.527-532
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    • 2014
  • $0.97Bi_{0.5+x}(Na_{0.78}K_{0.22})_{0.5-3x}TiO_3-0.03LaFeO_3$ lead-free piezoelectric ceramics were fabricated by a solid state reaction method. $LaFeO_3$ additives were added to $Bi_{0.5}(Na_{0.78}K_{0.22})_{0.5}TiO_3$ for volatile compensation of bismuth and sodium ions in the sintering process. To create A-site vacancies, the mole ratio and charge valence of A-site ions ($Bi^{3+}$, $Na^+$ and $K^+$) were controlled. The improved piezoelectric properties were observed by addition of $LaFeO_3$ and control of A-site vacancies. In particular, a $d_{33}^*(S_{max}/E_{max})$ value of 614pm/V and an electric field induced strain of 0.33% was observed in $0.97Bi_{0.505}(Na_{0.78}K_{0.22})_{0.485}TiO_3-0.03LaFeO_3$ ceramic.

Reactive Templated Grain Growth법에 의해 제조된 (Bi0.5Na0.5)TiO3-BaTiO3 세라믹스의 압전 특성 (Piezoelectric properties of (Bi0.5Na0.5)TiO3-BaTiO3 ceramics prepared by reactive templated grain growth method)

  • 안병국
    • 센서학회지
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    • 제16권3호
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    • pp.234-239
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    • 2007
  • Crystallographically {h00}-oriented $0.94(Bi_{0.5}Na_{0.5})TiO_{3}-0.06BaTiO_{3}$ (0.94BNT-0.06BT) ceramics was prepared by the Reactive Templated Grain Growth (RTGG) method using the $Bi_{4}Ti_{3}O_{12}$ template. The sheets prepared by tape-casting of slurries containing the templates and starting materials are cut, laminated, and pressed. Then burn-out and sintering was conducted. Also, to compare with the 0.94BNT-0.06BT ceramics prepared by the RTGG method another 0.94BNT-0.06BT ceramics was prepared by the solid-state method. In the optimum of this experiments range, the degree of orientation of the 0.94BNT-0.06BT ceramics prepared by the RTGG method was texture fraction${\approx}92%$ and the piezoelectric constant($d_{33}$) and coupling factor($k_{p}$) was obtained to $d_{33}{\approx}205{\;}pC/N$, $k_{p}{\approx}0.33%$, respectively.

Pb-free PTC에 있어서 $(Bi_{0.5}K_{0.5})TiO_3$ 첨가에 따른 $Ba_{1-x}(Bi_{0.5}K_{0.5})TiO_3$의 전기적특성 (Electrical Properties of $Ba_{1-x}(Bi_{0.5}K_{0.5})TiO_3$ according to $(Bi_{0.5}K_{0.5})TiO_3$ for Pb-free PTC)

  • 이미재;최병현;백종후;김빛남;이우영
    • 한국전기전자재료학회:학술대회논문집
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    • 한국전기전자재료학회 2008년도 추계학술대회 논문집 Vol.21
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    • pp.35-36
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    • 2008
  • PTC thermistor are characterized by an increase in the electrical resistance with temperature. The PTC materials of middle Curie point were produced or that of high Curie point (above $200^{\circ}C$), it was determined that compositional modifications of $Pb^{2+}$ for $Ba^{2+}$ produce change sin the Curie point to higher temperature. PTC ceramic materials with the Curie point above $120^{\circ}C$ were prepared by adding $PbTiO_3$, PbO or $Pb_3O_4$ into $BaTiO_3$. Thereby, adding $Pb^{2+}$ into $BaTiO_3$-based PTC material to improve Tc was studied broadly, however, weal know that PbO was poisonous and prone to volatilize, then to pollute the circumstance and hurt to people, so we should dope other innocuous additives instead of lead to increase Tc of composite PTC material. In order to prepare lead-free $BaTiO_3$-based PTC with middle Curie point, the incorporation on $Bi_{1/2}K_{1/2}TiO_3$ into $BaTiO_3$-based ceramics was investigated on samples containing 0, 1, 2, 3, 4, and 50mol% of $Bi_{1/2}K_{1/2}TiO_3$. $Bi_{1/2}K_{1/2}TiO_3$ was compounded as standby material by conventional solid-state reaction technique. The starting materials were $Bi_2O_3$, $K_2CO_3$, $BaCO_3$ and $TiO_2$ powder, and using solid-state reaction method, too. The microstructures of samples were investigated by SEM, DSC, XRD and dielectric properties. Phase composition and lattice parameters were investigated by X-ray diffraction.

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$Nb_2O_5$가 도핑된 (1-x)$BaTiO_3$ - $x(Bi_{0.5}K_{0.5})TiO_3$ 무연 세라믹스의 PTCR 효과 (The PTCR Effect in Lead-free (1-x)$BaTiO_3$ - $x(Bi_{0.5}K_{0.5})TiO_3$ Ceramics Doped with $Nb_2O_5$)

  • 정영훈;박용준;이영진;백종후;이우영;김대준
    • 한국전기전자재료학회:학술대회논문집
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    • 한국전기전자재료학회 2008년도 하계학술대회 논문집 Vol.9
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    • pp.52-52
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    • 2008
  • The positive temperature coefficient of resistivity (PTCR) effect in (1-x)$BaTiO_3$ - $x(Bi_{0.5}K_{0.5})TiO_3$ doped with $Nb_2O_5$ was investigated. $(Bi_{1/2}K_{1/2})TiO_3$ (BKT) is more environment-friendly than $PbTiO_3$ in order to use in PTC thermistors. The incorporation of 1 mol% BKT to $BaTiO_3$ increased the Curie temperature (Tc) to $148^{\circ}C$. Doping of $Nb_2O_5$ to $Ba_{0.99}(Bi_{0.5}K_{0.5})_{0.01}TiO_3$ (BaBKT) ceramic has enhanced its PTCR effects. For the sample containing 0.025 mol% $Nb_2O_5$, it showed good PTCR properties; low resistivity at room temperature (${\rho}_r$) of 30 $\Omega{\cdot}cm$, a high PTCR intensity of approximately $3.3\times10^3$, implying the ratio of maximum resistivity to minimum resistivity (${\rho}_{max}/{\rho}_{min}$) in the measured temperature range, and a large resistivity temperature factor (a) of 13.7%/$^{\circ}C$ along with a high Curie temperature (Tc) of $167^{\circ}C$. In addition, the cooling rate of the samples during the sintering process had an influence on their PTCR behavior. All the samples showed the best ${\rho}_{max}/{\rho}_{min}$ ratio when they have cooled down at a rate of $600^{\circ}C$/min.

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