• 한국전기전자재료학회논문지
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• 제25권6호
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• pp.435-438
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• 2012

As lead-free piezoelectric materials, $Ag_2O$ doped $0.95(K_{0.5}Na_{0.5})NbO_3-0.05LiNbO_3+x$ mol% (where x = 0, 0.5, 1, 1.5, 2, 2.5 and 3, respectively) ceramics were fabricated by a conventional sintering process. The doping effects on the microstructure and electrical properties of the $0.95(K_{0.5}Na_{0.5})NbO_3-0.05LiNbO_3$ ceramics were systematically investigated. When the 3 mol % $Ag_2O$ doped $0.95(K_{0.5}Na_{0.5})NbO_3-0.05LiNbO_3$ samples were sintered at $1,080^{\circ}C$ for 5 hrs in air, these ceramics showed excellent values of density=4.20 $g/cm^3$, piezoelectric constant ($d_{33}$)=174 pC/N and phase transition temperature$(T_c)=421.6^{\circ}C$, respectively.

• 한국결정성장학회지
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• 제12권1호
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• pp.27-30
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• 2002

Liquid phase epitaxy(LPE)법을 이용하여 ZnO co-doped Er:$LiNbO_3$, 단결정 박막을 $LiNbO_3$ (001) 기판 위에 성장시켰다. ZnO co-doped Er:$LiNbO_3$박막 성장의 초기 융액은 첨가제 $Er_2O_3$ 농도를 1 mol%로 고정시키고 ZnO 농도를 3,5 mol%로 조절하였다. ZnO co-doped Er :$LiNbO_3$박막의 결정성은 $LiNbO_3$ 기판보다 더 우수하였다. ZnO 5mol% 첨가한 경우 박막의 표면에는 수직한 방향과 평행한 방향으로 모두 압축응력이 작용하고 있었다. 또한 ZnO 3mol% 첨가된 Er :$LiNbO_3$박막의 표면은 원래의 $LiNbO_3$기판보다 더 평탄하였다

• 한국광물학회지
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• 제15권1호
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• pp.59-68
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• 2002

캐나다 퀘벡 주 오카지역에서 산출되는 네오비움 페롭스카이트(일명 라트라파이트, $Ca_2NbFe^{3+}O_6$)에 대하여 화학분석과 분말 X선 회절 데이터를 이용한 리트벨트 구조분석을 실시하였다. 라트라파이트는 $CaTiO_3-NaNbO_3-Ca_2NbFe^{3+}O_6$의 연속계열 고용체의 성분을 가지며, 화학분석 결과 평균$(Ca_{1.5}Na_{0.4})\;(Nb_{0.1}Ti_{0.6}Fe_{0.4})O_6$ 리트벨트 구조분석 결과 라트라파이트의 구조는 페롭스카이트($CaTiO_3$)의 결정구조와 유사하지만, Ti 이온이 Nb와 $Fe^{3+}$에 의해 치환되면서 상당히 뒤틀리고, $TiO_6$ 팔면체가 페롭스카이트에 비해 서로 기울어져 있는 모습을 보여준다 새롭게 결정된 라트라파이트의 공간군은 Pbnm, 단위포는 a=5.4474(4), b=5.5264(4), c=7.7519(5) ${\AA},\;V=233.4(3){\AA}^3$이다.

• 한국세라믹학회:학술대회논문집
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• 한국세라믹학회 2000년도 추계총회,초청강연,특별강연,연구발표회
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• pp.66.2-66
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• 2000

• 한국세라믹학회지
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• 제31권12호
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• pp.1443-1448
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• 1994

Pb(Mg1/3Nb2/3)O3-PbTiO3-BaTiO3 solid solution was formed by mixed-oxide method. The phase during formation was analysed by XRD and formation mechanism was investigated. While heat-treating Pb(Mg1/3Nb2/3)O3 composition, the first, Pb2Nb2O7 and Pb3Nb2O8 pyrochlore phases are formed, and finally Pb(Mg1/3Nb2/3)O3 perovskite phase with containing Pb3Nb4O13 pyrochlore phase is obtained at 80$0^{\circ}C$. When Pb(Mg1/3Nb2/3)O3 composition is modified with PbTiO3 which have strong ionic bonding and high tolerance factor, the amount of pyrochlore phase is decreased by increasing of stability in perovskite structure.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2001년도 추계학술대회 논문집 Vol.14 No.1
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• pp.426-429
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• 2001

The $BaTiO_{3}+xNb_{2}O_{5}$[x=6, 8, 10wt%] ceramics were prepared by conventional mixed oxide method. The structural properties of the $BaTiO_{3}+xNb_{2}O_{5}$ ceramics with the sintering temperature and addition of $Nb_{2}O_{5}$ were investigated by XRD and SEM. Increasing the sintering temperature, the $2{\Theta}$ value of BT (110) peak was shifted to the lower degree and intensity of the BN (310) peak was increased. Increasing the addition of $Nb_{2}O_{5}$, the intensity of BN (100) peak was decreased and BN (310), (110) peaks were increased. The grain size of the $BaTiO_{3}+xNb_{2}O_{5}$ ceramics sintered at $1350^{\circ}C$ were almost uniform. In the $BaTiO_{3}+xNb_{2}O_{5}$ ceramics sintered at $1350^{\circ}C$, the dielectric constant and dielectric loss were 5424, 0.02 respectively.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2001년도 추계학술대회 논문집
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• pp.426-429
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• 2001

The BaTiO$_3$+xNb$_2$O$_{5}$[x=6,8 , 10wt%] ceramics were prepared by conventional mixed oxide method. The structural properties of the BaTiO$_3$+xNb$_2$O$_{5}$ ceramics with the sintering temperature and addition of Nb$_2$O$_{5}$ were investigated by XRD and SEM. Increasing the sintering temperature, the 2$\theta$ value of BT (110) peak was shifted to the lower degree and intensity of the BN (310) peak was increased. Increasing the addition of Nb$_2$O$_{5}$, the intensity of BN (100) Peak was decreased and BN (310), (110) peaks were increased. The grain size of the BaTiO$_3$+Nb$_2$O$_{5}$ ceramics sintered at 135$0^{\circ}C$ were almost uniform. In the BaTiO$_3$+Nb$_2$O$_{5}$ ceramics sintered at 135$0^{\circ}C$, the dielectric constant and dielectric loss were 5424, 0.02 respectively.espectively.

• 한국세라믹학회지
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• 제30권9호
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• pp.723-730
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• 1993

The mechanism of formation of perovskite phase and the dielectric properties of PZMN[Pb(Zn, Mg)1/3Nb2/3O3] ceramics were examined using two different types of the columbite precursors, (Mg, Zn)Nb2O6 (MZN) and MgNb2O6＋ZnNb2O6 (MN＋ZN). The formatin of perovskite phase in PbO＋MN＋ZN system is characterized by an initial rapid formation of Mg-rich perovskite phase, followed by a sluggish formation of Zn-rich perovskite phase. On the other hand, thepyrochlore/perovskite transformation in the PbO＋MZN system proceeded uniformly with a spatial homogeneity. The degree of diffuseness of the rhombohedral/cubic phase transitionis higher in the PbO＋MN＋ZN system than in the PbO＋MZN specimen, indicating a broadened compositional distributjion of the B-site catons (Nb+5, Zn+2, Mg+2) in the PbO＋MN＋ZN system.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2007년도 추계학술대회 논문집
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• pp.245-245
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• 2007

본 연구는 $Bi_2O_3$, ZnO 및 $Nb_2O_5$로 이루어진 두 가지의 $Bi_2(Zn_{1/3}Nb_{2/3})_2O_7$와 $(Bi_{1.5}Zn_{0.5})(Zn_{0.5}Nb_{1.5})O_7$ pyrochlore를 제조한 후, ZBS 및 BZBS 유리를 각각 첨가하여 저온 소결 및 마이크로파 유전 특성을 고찰하였다. 두 가지의 pyrochlore에 대하여 하소 온도에 따른 상 합성 유무를 고찰한 결과 $900^{\circ}C$에서 단일 상을 갖는 pyrochlore를 제조할 수 있었다. 두 가지의 pyrochlore에 ZnO-rich ZBS 유리와 $Bi_2O_3$-rich BZBS 유리를 3, 5 wt%로 첨가한 후 $800{\sim}950^{\circ}C$에서 소결한 결과 ZBS 및 BZBS 유리를 5wt%를 첨가하였을 때 $900^{\circ}C$에서 소결이 가능하였다. 또한 마이크로파 유전 특성을 고찰한 결과, $(Bi_{1.5}Zn_{0.5})(Zn_{0.5}Nb_{1.5})O_7$의 pyrochlore는 고주파에서 유전 특성 측정이 되지 않았다. $Bi_2(Zn_{1/3}Nb_{2/3})_2O_7$의 pyrochlore의 경우 5 wt% ZBS 및 BZBS 유리를 첨가하여 $900^{\circ}C$에서 소결한 시편의 마이크로파 유전 특성은 ${\varepsilon}_r$= 62.8~68.3, $Q{\times}f$ value= 3,500~2,700 GHz을 나타내었다.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2001년도 하계학술대회 논문집
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• pp.402-405
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• 2001

The BaTiO$_3$+10wt%Nb$_2$O$_{5}$ ceramics were prepared by conventional mixed oxide method. The structural and dielectric properties of the BaTiO$_3$+10wt%Nb$_2$O$_{5}$ ceramics with the sintering temperature were investigated. Increasing the sintering temperature, the 2$\theta$ value of BaTiO$_3$peaks were shifted to the higher degree and intensity of the BaTiO$_3$and BaNbO$_3$peaks were increased. In the BaTiO$_3$+10wt%Nb$_2$O$_{5}$ ceramics sintered at 135$0^{\circ}C$ and 1375$^{\circ}C$, the grain was fine and uniform. Increasing the sintering temperature, the pore was decreased and the dielectric constant was increased. In the BaTiO$_3$+10wt%Nb$_2$O$_{5}$ ceramics sintered at 1375$^{\circ}C$, the dielectric constant and dielectric loss were 5424, 0.02 respectively.ctively.