• Title/Summary/Keyword: Electrostrictive Ceramic

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Analysis of a Conducting Crack in an Electrostrictive Ceramic Under Combined Electric and Mechanical Loading

  • Beom, Hyeon-Gyu;Jeong, Kyoung-Moon;Jeong, Eun-Do
    • Journal of Mechanical Science and Technology
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    • v.16 no.8
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    • pp.1117-1126
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    • 2002
  • A conducting crack in an electrostrictive ceramic under combined electric and mechanical loading is investigated. Analysis based on linear dielectric model predicts that the surfaces of the crack are not open completely but they are contact near the crack tip. The complete solution for the crack with a contact zone in a linear electrostrictive ceramic under combined electric and mechanical loading is obtained by using the complex variable formula. The asymptotic problems for a semi-infinite crack with a partial opening zone as well as for a fully open semi-infinite crack in a nonlinear electrostrictive ceramic are analyzed in order to investigate the effect of the electrical nonlinearity on the stress intensity factor under small scale nonlinear conditions. Particular attention is devoted to a finite crack in the nonlinear electrostrictive ceramic subjected to combined electric and mechanical loading. The stress intensity factor for the finite crack under small scale nonlinear conditions is obtained from the asymptotic analysis.

Analysis of a Crack in a Linear Electrostrictive Ceramic Subjected to Electric Fields (전기장을 받는 선형 전왜세라믹 내의 균열해석)

  • Beom, Hyeon-Gyu;Jeong, Gyeong-Mun;Gang, Sang-Hyeon
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.25 no.2
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    • pp.235-241
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    • 2001
  • A crack with electrically conducting surfaces in a linear electrostrictive ceramic subjected to uniform electric fields is analyzed. Complete forms of electric fields and elastic fields for the crack are derived by using the complex function theory. The linear electromechanical theory predicts overlapping of the traction free crack surfaces. It is shown that the surfaces of the crack are contact near the crack tip. The contact zone size obtained on the basis of the linear dielectric theory for the conducting crack does not depend on the electric fields and depends on only the original crack and the material property for the linear electrostrictive ceramic.

Effect of Excess MgO on Dielectric and Electrostrictive Properties of $0.99Pb(Mg_{1/3}Nb_{2/3})O_3-0.01Pb(Mn_{2/3}W_{1/3})O_3$ ($0.99Pb(Mg_{1/3}Nb_{2/3})O_3-0.01Pb(Mn_{2/3}W_{1/3})O_3$계의 유전 및 전왜 특성에 미치는 과잉 MgO의 영향)

  • 윤기현;김승연;남윤우;조용수;강동헌
    • Journal of the Korean Ceramic Society
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    • v.30 no.8
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    • pp.629-634
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    • 1993
  • Dielectric and electrostrictive properties of 0.99Pb(Mg1/3Nb2/3)O3-0.01Pb(Mn2/3W1/3)O3 system using KCl-NaCl salts have been investigated as a function of the amount of excess MgO. For the specimens calcined at $700^{\circ}C$ for 1h and then sintered at 115$0^{\circ}C$ for 4h, the perovskite phase and the relative density were about 98% and 95%, respectively. With the addition of excess MgO up to 10mol%, the dielectric constant and the electrostrictive strain increased due to the increase of density and grain size, and these properties were degraded by the further addition of excess MgO. For the 10mol% excess MgO added specimen, the maximum electrostrictive strain, Xmax, and the electrostrictive coefficient, Q11, were 4.5$\times$10-4, 3.5$\times$10-2m4/C2, respectively. These results were correlated with the property of PMW and microstructure.

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The Characteristics of Piezoelectric Strian Constants on PNN-PZ-PT Ceramics (PNN-PZ-PT계 세라믹스의 압전변위특성)

  • 정수태;남효덕;조상희
    • Journal of the Korean Ceramic Society
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    • v.26 no.6
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    • pp.802-810
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    • 1989
  • The temperature dependence of piezoelectric strain constant and the electric field induced strain are investigated as a function of PT in 0.5[xPT-(1-x)PZ]-0.5PNN ceramics. The piezoelectric strain constant d31 has the highest value(360$\times$10-12m/V) at PT=0.68. The temperature dependence of d31 is improved as Curie temperature of sample is increased, and the electric field dependence of induced strain is decreased with the coercive field increased. This ceramic system shows both piezoelectric effect and electrostrictive effect under the applied electric field. The piezoelectric of tetragonal phase is higher than that of rhombohedral phase, and the magnitude of electrostrictive constant is appeared in the order of morphotropic, rhombohedral and tetragonal phase. The piezoelectric strain constant with applied field must be considered theelectrostrictive effect due to 90$^{\circ}$domain wall displacements, and the displacement of bimorph type actuator agrees with the calulated value well.

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Dielectric and strain properties of Pb(Mg$_{1/3}$Nb$_{2/3}$)O$_{3}$-PbTiO$_{3}$ Ceramic with Respect to the Variation of SrTiO$_{3}$ Substitution (SrTiO$_{3}$ 고용에 따른 Pb(Mg$_{1/3}$Nb$_{2/3}$)O$_{3}$-PbTiO$_{3}$계 세라믹스의 유전 및 전왜특)

  • 지승한;이해영;이덕출;이진걸;이연학
    • The Transactions of the Korean Institute of Electrical Engineers
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    • v.45 no.2
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    • pp.235-241
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    • 1996
  • In this paper dielectric and electrostrictive strain properties of (1-y-x)Pb(Mg$_{1/3}$Nb$_{2/3}$)O$_{3}$-PbTiO$_{3}$$-yPbTiO_{3}-xSrTiO_{3}[(1-y-x)PMN-yPT-xST]$ ceramics fabricated by using columbite precursor method have been investigated with the substitution of SrTiO$_{3}$(ST). Dielectric constant of the specimens increased with the increase of ST content up to 5[m/o] and decreased with further substitution of ST. And the pyrochlore phase decreased with the increase of ST content up to 5[m/o] in XRD analysis. The elimination of the pyrochlore phase improved dielectric constants. The electrostrictive strains generated by AC electric field have the highest value at 5[m/o] SrTiO$_{3}$ addition and the hysteresis of strain ranged from 12 to 20[%]. The electrostrictive strain at various temperature investigated in the temperature range of $-50[^{\circ}C]~74[^{\circ}C].$ In higher temperature than phase transition region, it showed paraelectric property which shows very small hystersis.

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Effect of PbTiO3 Concentration on the Properties of $Pb(Mg_{1/3}Nb_{2/3})O_3-PbTiO_3$ Relaxor Ferroelectrics -II. Phase Transition and Electric-field-induced Strains- ($Pb(Mg_{1/3}Nb_{2/3})O_3-PbTiO_3$계 완화형 강유전체의 특성에 미치는 PbTiO3 첨가량의 영향 -II. 상전이 및 전계인가 변위특성-)

  • 박재환;김인태;김동영;조서용;흥국선;박순자
    • Journal of the Korean Ceramic Society
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    • v.33 no.5
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    • pp.556-562
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    • 1996
  • In order to understand the electrostrictive behavior of Pb(Mg1/3Nb2/3)O3-PbTiO3 (PMN-PT) solid solutions the dielectric constants the electric-field-induced strains and the pyroelectric coefficients of (1-x)PMN-xPT (x=0.1-0.4) were investigated in the temperature range -50~20$0^{\circ}C$. For x=0.1~0.35 where the phase transi-tion is diffusive the strain has a maxima at the temperature of maximum pyroelectric coefficient (depolrizing temperature) rather than the temperature of maximum dielectric constant. For x=0.4 where the phase transition is relatively sharp the strain decreases monotonically as the temperature increases. Relationships among the above experimental results are discussed.

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Phenomenological Analysis of Piezoelectric Properties in 0.88Pb(Zn1/3Nb2/3)O3−0.12PbTiO3 Single Crystals with an Engineering Domain Configuration

  • Ha, Jong-Yoon;Kim, Jin-Sang;Jeong, Dae-Yong;Kim, Hyun-Jai;Yoon, Seok-Jin
    • Journal of the Korean Ceramic Society
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    • v.45 no.3
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    • pp.139-141
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    • 2008
  • The piezoelectric properties of tetragonal 0.88Pb$(Zn_{1/3}Nb_{2/3)O_3-0.12PbTiO_3$ single crystals are characterized along the <111> direction, which composed the engineering domain configuration in the tetragonal phase. The <111>-oriented crystal possessed smaller $d_{33}$ values compared to the crystal along the <001> spontaneous polarization direction. Based on phenomenological theory, it is shown that the engineering domain configuration does not enhance the piezoelectric constant in tetragonal 0.88Pb$(Zn_{1/3}Nb_{2/3)O_3-0.12PbTiO_3$ single crystals. In addition, the electrostrictive coefficients of $Q_{12}=-0.03706m^4/C^2,\;Q_{11}=0.10765m^4/C^2,\;and\;Q_{44}=0.02020m^4/C^2$ of tetragonal 0.88PZN-0.12PT single crystals were calculated.

Dielectric properties of PZN-BT-PT composite ceramics (PZN-BT-PT계 복합 세라믹스의 유전특성에 관한 연구)

  • 이용우;류주현;윤현상;박창엽;정영호;하복남
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 1998.11a
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    • pp.41-44
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    • 1998
  • (1-X)LTC-XHTC composites were manufactured with the variation of X in the range of 0.3 $\leq$X $\leq$0.6 and its dielectric properties were investigated. Here, LTC and HTC are PZN-BT-PT -based ceramics with quire temperature(Tc) of 100。 C-3$0^{\circ}C$, respectively. 0.6HTC-0.4LTC composite ceramics show excellent values of $\Delta$$\varepsilon$$_{r}$/$\varepsilon$[%] which were -7.1% at -2$0^{\circ}C$ and -12% at 5$0^{\circ}C$, respectively. It is thought that composite ceramics with above results can be applied to electrostrictive actuator, high voltage ceramic capacitor etc.mic capacitor etc.r etc.c.

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