• 제목/요약/키워드: $LiBiO_2-CuO$

검색결과 26건 처리시간 0.029초

저온소성용 PZT 세라믹스의 치밀화에 미치는 첨가제의 영향 (Influence of Additives on Densification of Low-Temperature PZT Ceramics)

  • 박용갑
    • 한국산학기술학회논문지
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    • 제8권5호
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    • pp.995-999
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    • 2007
  • 저온 소결용 압전 세라믹 소결체의 치밀화에 미치는 첨가제의 영향을 조사하기 위하여 $PbZrTiO_3$(PZT) 분말을 제조하였으며, 이 PZT 분말을 이용하여 제조한 압전 세라믹스의 치밀화에 미치는 첨가제의 영향을 조사하였다. 첨가제는 $wB_2O_3-xBi_2O_3-zCuO$$LiBiO_2-CuO$ 두 종류가 제조되었으며 이 들 첨가제의 양을 변화 시켜 효과를 조사하였다. PZT 분말에 소결조제로서 1wt.% 의 $LiBiO_2-CuO$를 첨가하여 시편을 제조한 후, $800{\sim}1200^{\circ}C$까지의 온도 범위에서에서 소결한 결과 $900^{\circ}C$에서 최고의 소결밀도를 나타내었다. 소결된 압전체의 결정상을 분석하기 위하여 X-선회절분석을 시행하였으며, $900^{\circ}C$의 저온에서 소결한 $PbZrTiO_3$의 시편의 미세조직을 관찰하기 위하여 주사전자현미경(SEM)을 이용하였다. X-선 회절분석에서는 잘 발달된 PZT 상이 나타났으며, SEM 관찰 결과 평균입경은 $2{\sim}4\;{\mu}m$의 페로브스카이트 결정으로 균일하고 치밀한 조직을 나타내었으며, 높은 소결성은 첨가제에 의한 액상소결에 기인한다.

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급속반응공정에 의한 동 테이프 $Bi_{2}Sr_{2}CaCu_{2}O_{8}$ (Fabrication of $Bi_{2}Sr_{2}CaCu_{2}O_{8}$ Superconducting Films by the LiReac-PreCu Method)

  • 성현태;한상철;한영희;이준성;최희락
    • 한국초전도ㆍ저온공학회논문지
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    • 제1권1호
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    • pp.7-14
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    • 1999
  • Wekk oriented $Bi_{2} Sr_{2} CaCu_{2} O_{8}$ suppercondcting thick films were fabricared on copper tape by LiReac-PreCu (liquid reaction between a Cu-free precousor and Cu tape) method. Cu-free precursor power which is composed of $Bi_{2}Sr_{2}Ca_{5}$ was printed on a copper tape by screen printing and was heat-treated. The speciment were partially in a molten state at the heat treatment temperature (85$0^{\circ}C$~87$0^{\circ}C$). The heat heat treatments for the reaction were performed in air or low oxygen pressure in several stages. XRD analyses of the resulting Bi2Sr2CaCu2O8 superconducting tapes show that the $Bi_{2} Sr_{2} CaCu_{2} O_{8}$ phase is dominant and a small amount of $Bi_{2} Sr_{2} Cu_{2} O_{6}$ phase is detected. Both phases are aligned in the c-axis direction.

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소결조제 변화에 따른 PCW-PMN-PZT세라믹스의 저온소결 및 압전특성 (Low Temperature Sintering and Piezoelectric Properties of PCW-PMN-PZT Ceramics with the Variation of Sintering Aids)

  • 정광현;이덕출;류주현
    • 한국전기전자재료학회논문지
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    • 제17권12호
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    • pp.1320-1325
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    • 2004
  • In this study, in order to develop the low temperature sintering ceramics for multilayer piezoelectric transformer, PCW-PMN-PZT ceramics added with Li$_2$CO$_3$, Bi$_2$O$_3$ and CuO as sintering aids were manufactured, and their microstructural, dielectric and piezoelectric properties were investigated. When the only CuO was added, specimens could not be sintered below 98$0^{\circ}C$. However, when Li$_2$CO$_3$ and Bi$_2$O$_3$ were added, specimens could be sintered below 98$0^{\circ}C$. Li$_2$CO$_3$ and Bi$_2$O$_3$ addition were proved to lower sintering temperature of piezoelectric ceramics due to the effect of Li$_2$O-Bi$_2$O$_3$ liquid phase. Li$_2$CO$_3$ and Bi$_2$O$_3$ added specimens showed higher piezoelectric properties than those of the only CuO added specimens. At 0.2 wt% Li$_2$CO$_3$ and 0.3 wt% Bi$_2$O$_3$ added specimen sintered at 92$0^{\circ}C$, the dielectric constant of 1457, electromechanical coupling factor of 0.56 and mechanical quality factor of 1000 were shown, respectively. These values are suitable for multilayer piezoelectric transformer application.

Li2O-Bi2O3 첨가가 Pb(Mg1/3Nb2/3)0.65Ti0.35O3 세라믹의 압전 특성에 미치는 영향 (Effect of Li2O-Bi2O3 Addition on the Piezoelectric Properties of Pb(Mg1/3Nb2/3)0.65Ti0.35O3 Ceramics)

  • 김재혁;김시연;최정식;여동훈;신효순;남산
    • 한국분말재료학회지
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    • 제26권5호
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    • pp.405-409
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    • 2019
  • Piezoelectric ceramic specimens with the $Pb(Mg_{1/3}Nb_{2/3})_{0.65}Ti_{0.35}O_3$ (PMN-PT) composition are prepared by the solid state reaction method known as the "columbite precursor" method. Moreover, the effects of the $Li_2O-Bi_2O_3$ additive on the microstructure, crystal structure, and piezoelectric properties of sintered PMN-PT ceramic samples are investigated. The addition of $Li_2O-Bi_2O_3$ lowers the sintering temperature from $1,200^{\circ}C$ to $950^{\circ}C$. Moreover, with the addition of >5 wt.% additive, the crystal structure changes from tetragonal to rhombohedral. Notably, the sample with 3 wt.% additive exhibits excellent piezoelectric properties ($d_{33}=596pC/N$ and Kp = 57%) and a sintered density of $7.92g/cm^3$ after sintering at $950^{\circ}C$. In addition, the sample exhibits a curie temperature of $138.6^{\circ}C$ at 1 kHz. Finally, the compatibility of the sample with a Cu electrode is examined, because the energy-dispersive X-ray spectroscopy data indicate the absence of interdiffusion between Cu and the ceramic material.

CuO 첨가된 저온소결 (Na,K,Li)(Nb,Sb,Ta)O3계 세라믹스의 압전 및 유전 특성 (Piezoelectric and Dielectric Properties of Low Temperature Sintering (Na,K,Li)(Nb,Sb,Ta)O3 Ceramics Doped with CuO)

  • 이광민;류주현;이지영
    • 한국전기전자재료학회논문지
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    • 제28권4호
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    • pp.229-233
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    • 2015
  • In this paper, in order to develop outstanding Pb-free piezoelectric composition ceramics, the $(Na_{0.525}K_{0.443}Li_{0.037})(Nb_{0.883}Sb_{0.08}Ta_{0.037})O_3+0.3wt%Bi_2O_3+0.4wt%Fe_2O_3+xwt%CuO$ (x= 0~0.8 wt%)(abbreviated as NKL-NST) lead-free piezoelectric ceramics have been synthesized using the ordinary solid state reaction method. The effects of CuO-doping on the structure and electrical properties of the NKL-NST ceramics were systematically studied. The results show that the ceramics exhibit a pure perovskite structure with orthorhombic phase at room temperature, and secondary phase was found in the ceramics. The 0.4 wt%CuO added ceramics sintered at $950^{\circ}C$ showed the optimum properties of piezoelectric constant($d_{33}$), planar piezoelectric coupling coefficient(kp) and mechanical quality factor(Qm) : $d_{33}=213$[pC/N], kp= 0.43, Qm= 423,respectively.

Cu-free 비정질체를 이용한 동 테이프 위의 Bi계 초전도 후막 제조 (Fabrication of Bi System Superconducting Films on Cu Tape with Melt-Quenched Cu-free Materials)

  • 성태현;한상철;한영희;이준성;김상준
    • 한국초전도학회:학술대회논문집
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    • 한국초전도학회 1999년도 High Temperature Superconductivity Vol.IX
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    • pp.315-318
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    • 1999
  • Bi$_{2}Sr_{2}CaCu_{2}O_{\delta}$ superconducting films were rapidly fabricated on copper tape by liquid reaction between a Cu-free precursor and Cu tape (LiReac-PreCu) method. Those thick films were well oriented along the c-axis. The precursor was made by melt-quenched technology using twin roller. The melt-quenched films were transparent and glossy yellow in appearance. These films which were the compostion of Bi$_2SrCaO_y$, Bi$_3Sr_2CaO_z$ were placed on copper tape and then heated at various temperatures for several minutes in air. They were analyzed using X-ray powder diffraction, SEM, a DC four-probe method. The mechanism of superconducting phase formation . from the melt-quenched precursor on Cu tape was studied

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저온 소결제 첨가에 의한 LiNb3O8-TiO2계 세라믹스의 마이크로파 유전 특성 (Microwave Dielectric Properties of the LiNb3O8-TiO2 Ceramic System with the Addition of Low Firing Agents)

  • 최명호;김남철
    • 한국전기전자재료학회논문지
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    • 제21권6호
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    • pp.517-523
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    • 2008
  • The microwave dielectric properties of $LiNb_3O_8-TiO_2$ based ceramics with low firing agents, CuO, $Bi_2O_3$, $B_2O_3$, $SiO_2$, $TiO_2$, were investigated to improve the sintering condition for the LTCC system. According to the X-ray diffraction and SEM, the ceramics of $LiNb_3O_8-TiO_2$ with low firing agents showed no significant second phases within a range of experiments, and fine microstructures. By adding the low firing agents, the sintering temperature decreased from $1200^{\circ}C$ to $925^{\circ}C$. Based on the results of electrical measurements, the $LiNb_3O_8-TiO_2$ ceramics showed a promising microwave dielectric properties for LTCC applications, those are ${\varepsilon}_r$ (dielectric constant) = 44, Q f (quality factor) = 18000, and ${\tau}_f$ (the temperature coefficient of resonant frequency) = $-1.5\;ppm/^{\circ}C$.

Enhanced Piezoelectric Properties of (1-x)[0.675BiFeO3-0.325BaTiO3]-xLiTaO3 Ternary System by Air-Quenching

  • Akram, Fazli;Malik, Rizwan Ahmed;Lee, Soonil;Pasha, Riffat Asim;Kim, Myong Ho
    • 한국재료학회지
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    • 제28권9호
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    • pp.489-494
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    • 2018
  • Lead free $(1-x)(0.675BiFeO_3-0.325BaTiO_3)-xLiTaO_3$ (BFBTLT, x = 0, 0.01, 0.02, and 0.03, with 0.6 mol% $MnO_2$ and 0.4 mol% CuO) were prepared by a solid state reaction method, followed by air quenching and their crystalline phase, morphology, dielectric, ferroelectric and piezoelectric properties were explored. An X-ray diffraction study indicates that lithium (Li) and tantalum (Ta) were fully incorporated in the BFBT materials with the absence of any secondary phases. Dense ceramic samples (> 92 %) with a wide range of grain sizes from $3.70{\mu}m$ to $1.82{\mu}m$ were obtained in the selected compositions ($0{\leq}x{\leq}0.03$) of BFBTLT system. The maximum temperatures ($T_{max}$) were mostly higher than $420^{\circ}C$ in the studied composition range. The maximum values of maximum polarization ($P_{max}{\approx}31.01{\mu}C/cm^2$), remnant polarization ($P_{rem}{\approx}22.82{\mu}C/cm^2$) and static piezoelectric constant ($d_{33}{\approx}145pC/N$) were obtained at BFBT-0.01LT composition with 0.6 mol% $MnO_2$ and 0.4 mol% CuO. This study demonstrates that the high $T_{max}$ and $d_{33}$ for BFBTLT ceramics are favorable for industrial applications.

MBE, LPE와 $\mu$ - PD 기술에 의한 산화물재료의 개선된 단결정 성장방법 (Improved single crystal growth methods for oxide materials by MBE, LPE and $\mu$ - PD techniques)

  • 윤대호
    • 한국결정성장학회지
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    • 제5권4호
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    • pp.378-385
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    • 1995
  • 분자션 에피텍시얼(MBE)법, 액상 에피텍시열(LPE)법과 마이크로 인상($\mu$ - PD)법 에 의한 단결정 성장에 있어서의 새로운 접근을 논의하였다. 재료로써는 Bi-Sr-Ca-Cu계, $K_3Li_2Nb_5O_{15}$계의 산화물을 사용하였으며, 비평형영역으로 부터의 고품질(균일 조성 및 저결함 밀도) 결정성장은 원자수준의 계면제어에 의해 가능함을 고찰할 수 있였다.

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$(Na,Li)NbO_3-BaTiO_3$세라믹스의 유전 및 압전 특성

  • 성금현;이유형;류주현;정영호
    • 한국전기전자재료학회:학술대회논문집
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    • 한국전기전자재료학회 2009년도 추계학술대회 논문집
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    • pp.77-77
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    • 2009
  • $Pb(Zr,Ti_O_3$계 세라믹스는 우수한 압전 특성으로 인하여 압전변압기 및 액츄에이터, 센서 등 많은 분야에 응용이 되어져 왔다. 그러나, 최근 들어 $1000^{\circ}C$에서 급속도로 많은 휘발을 하는 PbO는 환경 및 인체에 나쁜 영향을 미칠 뿐 아니라 사용 후의 처리도 어려워 선진국에서는 사용을 제한하거나 줄이고 있는 추세에 있다. 따라서, PbO를 포함하지 않은 무연 (Lead-free)계 압전 세라믹스에 대한 연구가 많은 관심을 끌고 있으며 앞으로는E 장래성 있는 하나의 이슈 분야가 될 것이다. 이러한 Pb-based System 세라믹스를 대체 할 재료로서 $(Bi_{1/2}Na_{1/2})TiO_3$나 Tungsten-Bronze type, $(K_{1/2}Na_{1/2})NbO_3$ 등이 주로 연구가 되고 있다. 특히, alkali niobate를 기초로 한 $(K_{1/2}Na_{1/2})NbO_3(NKN)$은 무연 압전 물질로서 많은 주목을 받고 있다. 그러나, NKN의 주요 성분인 K 의 높은 조해성 때문에 일반적인 고상방법으로는 고 밀도의 세라믹을 얻기 힘들뿐더러 낮은 상전이 온도 때문에 많은 응용에는 제약이 되고 있다. 이러한 세라믹의 단점을 보완하고자 Hot forging, RTGG, SPS 등 과 같이 특수한 소결방법을 사용하여 고밀도의 세라믹을 제작하지만 이 방법들은 제품 대량 생산에 있어 경제적으로나 복잡한 제조과정을 고려할 때 매우 비효율적이라고 판단된다. 그러므로 $BaTiO_3$, $LiTaO_3$, Mg, Ca등을 첨가 시켜 소결을 향상시키고 고밀도를 얻기 위해 많은 연구가 진행 중이다. 따라서 본 연구에서는 Pb-based계의 세라믹스를 대체할 우수한 특성의 세라믹스를 제작하고자 기존의 $(K_{1/2}Na_{1/2})NbO_3(NKN)$세라믹스에서 낮은 용융온도 때문에 소결하기 어려운 $KNbO_3$를 제거한 $NaNbO_3$$LiNbO_3$$BaTiO_3$를 추가한 $NaLiNbO_3-BaTiO_3$세라믹스에 $K_4CuNb_8O_{23}$(KCN)을 첨가함으로서 이에 따른 압전 및 유전 특성을 조사하였다.

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