• Title, Summary, Keyword: $BaTiO_3$ ceramic

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Effect of $BaTiO_3$ Dispersion on the Properties of Cast Tapes in Processing of Multilayer Ceramic Capacitor(MLCC) (적층 세라믹콘덴서 제조공정에서 $BaTiO_3$의 분산이 테이프캐스팅 성형체의 물성에 미치는 영향)

  • 김봉호;김병관;김명호;백운규
    • Journal of the Korean Ceramic Society
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    • v.33 no.2
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    • pp.214-222
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    • 1996
  • The effect of physicochemical properties of organic solvent and dispersant among organic solvent dispersant binder and plasticizer which are used as processing additives in MLCC fabrication process on the dispersion of BaTiO3 was studied. The steric and electrostatic stabilization mechanisms in dispersion of BaTiO3 in organic media were evaluated respectively. The sttability of BaTiO3 achieved bysteric stabilization was dependent on the fraction of surface coverage of dispersant adsorption on BaTiO3. The electrostatic repulsive forces of BaTiO3 particles dispersed in orgainc media was found to be appreciabley great and dependent mainly on the kinds of organic solvent used. The mechanism affecting the stability of BaTiO3 was studied by the method of rheologi-cal behaviors of BaTiO3 suspension.

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Comparison of Experimental Values and Theoretical Predictions of the Dielectric Constant of Epoxy/BaTiO$_3$ Composite Embedded Capacitor Films (에폭시/BaTiO$_3$ 복합 내장형 커패시터 필름의 유전상수에 관한 실험값과 이론적 예측값과의 비교)

  • 조성동;이상용;현진걸;백경욱
    • Journal of the Microelectronics and Packaging Society
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    • v.11 no.1
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    • pp.87-96
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    • 2004
  • Polymer/ceramic composites are the most promising embedded capacitor material for organic substrates application. Predicting the effective dielectric constant of polymer/ceramic composites is very important for design of composite materials. In this paper, we measured the dielectric constant of epoxy/$BaTiO_3$ composite embedded capacitor films with various $BaTiO_3$ particles loading for 5 different sizes $BaTiO_3$ powders. Experimental data were fitted to several theoretical equations to find the equation useful for the prediction of the effective dielectric constant of polymer/ceramic composites and also to estimate the dielectric constant of $BaTiO_3$ powders. The Lichtenecker equation and the Jayasundere-Smith equation were useful for the prediction of the effective dielectric constant of epoxy/$BaTiO_3$ composites. And calculated dielectric constants of the $BaTiO_3$ powders were in the range of 100 to 600, which were lower than those of $BaTiO_3$ bulk ceramics.

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Effect of Ceramic Powder Content and Shape on the Electrical Properties of Ceramic(BaTiO3)-polymer(Epoxy) Composite for Embedded Capacitors (임베디드 커패시터용 세라믹(BaTiO3)-고분자(에폭시) 필름의 세라믹 분말 형상 및 함량에 따른 전기적 특성)

  • Han, Jeong-Woo;Yoon, Jung-Rag;Je, Hae-June;Lee, Dong-Ho;Lee, Kyung-Min
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
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    • v.22 no.6
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    • pp.495-500
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    • 2009
  • The ceramic($BaTiO_3$)-polymer(epoxy) composites have been widely investigated as dielectric materials for embedded capacitors in printed circuit boards (PCBs). The dielectric properties of $BaTiO_3$/epoxy composites prepared using the agglomerated $BaTiO_3$ particles were investigated in the present study. The dielectric constants of the composites prepared using the agglomerated $BaTiO_3$ particles were about 2 times higher than those of the composites with the dispersed $BaTiO_3$ particles. The insulation resistance of the composites prepared using the agglomerated $BaTiO_3$ particles were lower than those of the composites with dispersed $BaTiO_3$ particles. As a result, there is tradeoff between high dielectric constant and insulation resistance in the $BaTiO_3$/epoxy composites. So it is important to select proper agglomerated or dispersed $BaTiO_3$ particles in accordance with needs.

Electrical conductivity of $BaTiO_3$ under Ba/Ti Ratio (Ba/Ti 비에 따른 $BaTiO_3$의 전기전도도)

  • Yeo, Hong-Goo;Kim, Myong-Ho;Song, Tae-Kwon;Park, Tae-Gone;Lee, Soon-Il;Randall, Clive A.
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • pp.165-170
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    • 2004
  • MLCC의 주재료인 $BaTiO_3$는 금속전극의 산화를 방지하기 위해 환원분위기에서 소결하는데 이는 비화학양론적 조성 및 전기적 성질, 결함 그리고 상의 변화를 가져온다. 본 연구에서는 상의 변화를 다양한 온도 범위에서 BaO 또는 $TiO_2$를 첨가시킨 $BaTiO_3$ powder을 가지고 급냉시킨 후 이를 X-선 회절 분석을 통하여 이들의 이차상 형성 여부 등을 조사하였다. $1320^{\circ}C$에서는 $TiO_2$의 고용도가 BaO의 고용도에 비해 상당히 큰 값을 가짐을 알 수 있었다. 이런 결과를 바탕으로 Ba/Ti 비, 산소분압 및 온도에 따른 $BaTiO_3$의 전기전도도 거동에 의하면, 고용범위내에서 BaO 첨가량이 증가할수록 전기전도도의 최소점은 낮은 산소분압쪽으로 이동함을 관찰하였으며 이는 $Ti^{4+}$빈자리에 따른 산소빈자리가 형성되는 결함 모델로 설명되어진다.

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Fabrication of $BaTiO_3-PTCR$ Ceramic Resister Prepared by Direct Wet Process (습식 직접합성법을 이용한 PTCR 소자개발 연구)

  • 이경희;이병하;이희승
    • Journal of the Korean Ceramic Society
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    • v.22 no.4
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    • pp.61-65
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    • 1985
  • $BaTiO_3$ powders doped with $BaTiO_3$ and $Nb_2O_5$ at 9$0^{\circ}C$ for 1hr. were synthesized by Direct Wet Process. These powders were very homogeneous and fine particle size. To obtain the highe PTCR effect AST($1/3Al_2O_3$.$3/4SiO_2$.$1/4TiO_2$) and $MnO_2$ were added in the semiconduc-ting $BaTiO_3$. In this case $Bi_2O_3$ and $MnO_2$ were used in the form of $Bi(NO)_3$ and $MnCl_2$.$4H_2O$ solution for Direct Wet Process. $BaTiO_3$ doped Nb2O5 and $MnO_2$ demostrated greater PTCR effect than $BaTiO_3$ doped $Nn_2O_5$ only.

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Sintering and Electrical Characteristics of Semiconducting $BaTiO_3$ Ceramics with Addition of $BaB_2O_4$ ($BaB_2B_4$ 첨가에 따른 반도성 $BaTiO_3$ 세라믹스의 소결 및 전기적 특성)

  • 허영우;이준형;김정주;김남경;조상희
    • Journal of the Korean Ceramic Society
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    • v.33 no.9
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    • pp.1038-1044
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    • 1996
  • The variations of sintering and electrical characteristics of semiconducting BaTiO3 ceramics with sintering agents added were investigated comparing the case of BaB2O4 addition to BN and TiO2 addition. When BaB2O4 added in BaTiO3 ceramics the densitifcation of specimen could be acheived more easily and recvealed the better PTCR characteristics than BN and TiO2 addition. As increase of addition of BaB2O4 in BaTiO3 spec imens the slope of resistivity jump also increased but the temperature of maximum resistivity decreased, It was supposed that addition of BaB2O4 led to increase of Ns (acceptor state density) value at grain boundaries.

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A Study on Solid Reaction of BaCO3-TiO2 System (BaCO3-TiO2계의 고상반응에 관한 연구)

  • 이응상;황성연;임대영
    • Journal of the Korean Ceramic Society
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    • v.24 no.5
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    • pp.484-490
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    • 1987
  • Diffusion coupling experiment was done to study expansion of body and soild reaction in BaCO3-TiO2 system. Specimen of BaCO3 and TiO2 was formed with Pt-mark's method. Each specimen was fired at interval of 25℃ from 900℃ to 1000℃ for 2hrs. After that, specimen was fixed with resin and polished. Product layers of specimen were observed with SEM and EDS. The result were following; 1. Diffusion component is Ba2+, which diffuse toward TiO2. 2. Large crack between layer of BaCO3 and Ba2TiO4 was generated because of difference of thermal expansion coefficient. 3. Ba2TiO4 is formed to TiO2 body by the reaction of BaTiO3 and BaO and its structure is very porous. 4. BaTiO3 changes immediately to Ba2TiO4 by the reaction of BaO. But BaTiO3 which formed by the reaction of TiO2 and Ba2TiO4 exsists as layer because the diffusion distance of Ba2+ is far.

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Dielectric Properties of $BaTiO_3-SrTiO_3$ System ($BaTiO_3-SrTiO_3$ 계의 유전성)

  • 윤기현;이남양;조경화
    • Journal of the Korean Ceramic Society
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    • v.21 no.4
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    • pp.341-348
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    • 1984
  • $BaTiO_3$ and $SrTiO_3$ were mixed with the mole ratio of 35:65, 50:50 and 65:35 and heated at 1100~120$0^{\circ}C$ for 1~64 hours. The dielectrics of $BaTiO_3$-$SrTiO_3$ system were investigated as a function of amount of solid solution formed. The dielectric constant was increased and Curie temperature was shifted to higher temperature with increasing of heating of soaking time for the same composition and heating temperature. This can be explained by the homogeneous distribution of $Ba^{2+}$ and $Sr^{2+}$ ion in the $BaTiO_3$ system. The Curie temperature was shifted to lower temperature with increasing $SrTiO_3$ in the $BaTiO_3$-$SrTiO_3$system because of decreasing the lattice constant.

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Electrical properties of layered $BaTiO_3$ thin film (적층구조 $BaTiO_3$ 박막의 전기적 특성)

  • 송만호;윤기현
    • Journal of the Korean Ceramic Society
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    • v.34 no.2
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    • pp.181-187
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    • 1997
  • The layered BaTiO3 thin films with a high dielectric constant of polycrystalline BaTiO3 and a good in-sulating property of amorphous BaTiO3 were prepared. And their electrical properties were characterized with stacking methods. The BaTiO3 thin films were prepared by rf-magnetron sputtering technique using a ceramic target on Indium-doped Tin oxide coated glasses. A new stacking method resulted in higher dielec-tric constant, capacitance per unit area, and breakdown strength than those prepared by a conventional stacking method; the new method continuously decrease the substrate temperature after initial deposition of a polycrystalline BaTiO3 layer. The observed high dielectric constant could be explained only by a mul-tilayered amorphous/microcrystalline/polycrystalline structure, which was confirmed indirectly by AES depth profile.

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