• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2000년도 추계학술대회 논문집
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• pp.543-546
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• 2000

Ferroeleclric 0.05PZN-xPZT(90/10)-(0.95-x)PZT(10/90) (x=0.65, 0.85) specimens were fabricated by the mixed-oxide method and cold-pressing method using sol-gel derived PZT(90/10) and PZT(10/90) powders. All specimens show a uniform ferroelectric grain without the presence of the pyrocholre phase. Average grain size increased with an increase in sintering temperature, the value for the x=0.65 specimen sintered at 125$0^{\circ}C$ was 14.4$\mu$m. The dielectric constant and dielectric loss of the x=0.65 specimen sintered at 125$0^{\circ}C$ were 1247, 2.06%, respectively. All specimens showed fairly good temperature and frequency stability of dielectric constant with the range from -2$0^{\circ}C$ to 6$0^{\circ}C$ and 100Hz to 10MHz. The coercive field and the remanent polarization of x = 0.65 specimen sintered at 125$0^{\circ}C$ were 8.5 kV/cm and 13 $\mu$C/cm$^2$, respectively. The pyroelectric coefficient of the x=0.65 specimen sintered at 125$0^{\circ}C$ was 5.64$\times$10$^{-8}$ C/cm$^2$K, respectively.

• 한국지구과학회지
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• 제27권1호
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• pp.49-60
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• 2006

본 연구는 나주지역 하상퇴적물에 대한 지구화학적 특성 연구이다. 이를 위해 1차 수계를 대상으로 139개의 하상퇴적물 시료를 채취하였다. 채취된 시료는 실험실에서 자연 건조시켰으며, XRF, ICP-AES, NAA를 이용하여 화학분석을 실시하였다. 기반암에 따른 지구화학적 특성을 알아보기 위하여, 화강암질편마암 지역, 편암류 지역, 화강암류 지역, 사질암 지역, 응회암 지역, 안산암 지역, 유문암 지역으로 분류하였다. 나주지역 하상퇴적물의 지질집단별 주성분원소 평균함량은 $SiO_2\;58.37{\sim}66.06wt.%,\;Al_2O_3\;13.98{\sim}18.41wt.%,\;Fe_2O_3\;4.09{\sim}6.10wt.%,\;CaO\;0.54{\sim}1.33wt.%,\;MgO\;0.86{\sim}1.34wt.%,\;K_2O\;2.38{\sim}4.01wt.%,\;Na_2O\;0.90{\sim}1.32wt.%,\;TiO_2\;0.82{\sim}1.03wt.%,\;MnO\;0.09{\sim}0.15wt.%,\;P_2O_5\;0.11{\sim}0.18wt.%$이다. 주성분원소의 평균함량 비교에서 $Al_2O_3$와 $K_2O$는 화강암질편마암 지역에서, $Fe_2O_3,\;CaO,\;P_2O_5$는 응회암 지역에서, MgO와 $TiO_2$는 안산암 지역에서, $Na_2O$는 유문암 지역에서 높고, $SiO_2$와 MnO 함량은 사질암 지역에서 약간 높다. 미량성분 및 희토류원소의 지질집단별 평균함량은 $Ba\;1278{\sim}1469ppm,\;Be\;1.1{\sim}1.5ppm,\;Cu\;18{\sim}25ppm,\;Nb\;25{\sim}37ppm,\;Ni\;16{\sim}25ppm,\;Pb\;21{\sim}28ppm,\;Sr\;83{\sim}155ppm,\;V\;64{\sim}98ppm,\;Zr\;83{\sim}146ppm,\;Li\;32{\sim}45ppm,\;Co\;7.2{\sim}12.7ppm,\;Cr\;37{\sim}76ppm,\;Cs\;4.8{\sim}9.1ppm,\;Hf\;7.5{\sim}25ppm,\;Rb\;88{\sim}178ppm,\;Sc\;7.7{\sim}12.6ppm,\;Zn\;83{\sim}143ppm,\;Pa\;11.3{\sim}37ppm,\;Ce\;69{\sim}206ppm,\;Eu\;1.1{\sim}1.5ppm,\;Yb\;1.8{\sim}4.4ppm$이다. Pb, Li, Cs, Hf, Rb, Sb, Pa, Ce, Eu, Yb 평균함량은 화강암질편마암 지역에서, Ba, Co, Cr 평균함량은 편암류 지역에서, Nb, Ni, Zr 평균함량은 사질암 지역에서, Sr 평균함량은 응회암 지역에서 높고, Be, Cu, V, Sc, Zn 평균함량은 안산암 지역에서 다른 지질집단에서 보다 높다.

• 광물과 암석
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• 제33권3호
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• pp.195-214
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• 2020

삼광 금-은 광상은 과거 한국에서 가장 큰 금-은 광상들 중의 하나였다. 이 광상은 선캠브리아기의 변성퇴적암류내에 발달된 열극대를 충진한 8개조의 석영맥으로 구성된 조산형 금-은 광상이다. 이 광상에서 함 티타늄 광물로는 설석, 티탄철석 및 금홍석이며 설석과 티탄철석은 모암에서만 산출되나 금홍석은 모암과 엽리상 석영맥에서 산출된다. 이들 광물들은 모암에선 흑운모, 백운모, 녹니석, 백색운모, 모나자이트, 저어콘 및 인회석과 엽리상 석영맥에선 백색운모, 녹니석 및 유비철석 등과 함께 산출된다. 설석은 최대 3.94 wt.% (Al₂O₃), 0.49 wt.% (FeO), 0.52 wt.% (Nb₂O₅), 0.46 wt.% (Y₂O₃) 및 0.43 wt.% (V₂O₅) 값을 갖는다. 이 설석은 0.06~0.14 (Fe/Al 비) 값으로 변성기원의 설석이고 X_Al (=Al/Al+Fe³⁺+Ti) 값이 0.06~0.15 값으로 저 함량 알루미늄 설석에 해당된다. 티탄철석은 최대 0.07 wt.% (ZrO₂), 0.12 wt.% (HfO₂), 0.26 wt.% (Nb₂O₅), 0.04 wt.% (Sb₂O₅), 0.13 wt.% (Ta₂O₅), 2.62 wt.% (As₂O₅), 0.29 wt.% (V₂O₅), 0.12 wt.% (Al₂O₃), 1.59 wt.% (ZnO)로써 As₂O₅ 함량이 높게 산출된다. 금홍석의 화학조성은 모암과 엽리상 석영맥에서 각각 최대 0.35 wt.%, 0.65 wt.% (HfO₂), 2.52 wt.%, 0.19 wt.% (WO₃), 1.28 wt.%, 1.71 wt.% (Nb₂O₃), 0.03 wt.%, 0.07 wt.% (Sb₂O₃), 0.28 wt.%, 0.21 wt.% (As₂O₅), 0.68 wt.%, 0.70 wt.% (V₂O₃), 0.48 wt.%, 0.59 wt.% (Cr₂O₃), 0.70 wt.%, 1.90 wt.% (Al₂O₃), 4.76 wt.%, 3.17 wt.% (FeO)로써 엽리상 석영맥의 금홍석에서 HfO₂, Nb₂O₃, As₂O₅, Cr₂O₃, Al₂O₃ 및 FeO 원소들의 함량이 모암의 금홍석보다 높지만 WO₃ 원소의 함량은 낮다. 이 미량원소들은 모암의 금홍석[(Fe³⁺, Al³⁺, Cr³⁺) + Hf⁴⁺+(W⁵⁺, As⁵⁺, Nb⁵⁺) ⟵⟶; 2Ti⁴⁺+ V⁴⁺, 2Fe²⁺+(Al³⁺, Cr³⁺) + Hf⁴⁺+(W⁵⁺, As⁵⁺, Nb⁵⁺) ⟵⟶ 2Ti⁴⁺+2V⁴⁺], 엽리상 석영맥의 금홍석 [(Fe³⁺, Al³⁺) + As⁵⁺ ⟵⟶ Ti⁴⁺+ V⁴⁺, (Fe³⁺, Al³⁺) + As⁵⁺ ⟵⟶ Ti⁴⁺+Hf⁴⁺, 4(Fe³⁺, Al³⁺) ⟵⟶ Ti⁴⁺+(W⁵⁺, Nb⁵⁺) + Cr³⁺]로써 치환관계가 있었다. 이들 자료를 근거로, 모암내 산출되는 설석, 티탄철석 및 금홍석은 광역변성작용 동안 모암광물들의 변질 시 광물내 존재했던 W⁵⁺, Nb⁵⁺, As⁵⁺, Hf⁴⁺, V⁴⁺, Cr³⁺, Al³⁺, Fe³⁺, Fe²⁺ 등과 같은 양이온들의 재 용해 및 농집에 의해 형성되었다. 그후 계속된 연성전단 시 엽리상 석영맥내 금홍석은 열수 용액의 유입에 따른 백색운모와 녹니석의 모암변질작용에 의한 양이온들의 재 용해 및 재 농집과 더불어 초기에 형성된 설석, 티탄철석 및 금홍석과의 반응에 의해 기존에 이들 광물내에 존재하였던 Nb⁵⁺, As⁵⁺, Hf⁴⁺, Cr³⁺, Al³⁺, Fe³⁺, Fe²⁺과 같은 양이온들의 재농집에 의해 형성된 것으로 생각된다.

• KSBB Journal
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• 제13권5호
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• pp.477-482
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• 1998

A biosensor with PZT piezoelectric ceramic crystal was developed for the detection of formaldehyde gas. Poled PZT piezoelectric ceramic disk was made from ZrO2, TiO2 and Nb2O5, together with the addition of PbO and polyvinyl alcohol, through various processes of mixing, calcination drying, crushing, forming, sintering, polishing, ion coating and poling. Oscillator circuit of sensor was made of operational amplifier(AD811AN). Formaldehyde dehydrogenase was immobilized onto a piezoelectic ceramic crystal, together with the cofactors, reduced glutathione and nicotinamide adenine dinucleotide. The effect of flow rate on the sensitivity was determined by varing the flow rate of carrier gas from 24.7mL/min to 111.7mL/min through detector cell. The results indicated that as the flow rate was increased, the recovery rate was increased. And a significant increase in the sensitivity was observed in enhanced flow rate of carrier gas. Frequency difference(ΔF) of immobilized PZT piezoelectic disk increased proportionally to the concentration gas and reproduced to repeated exposures of formaldehyde gas(28ppm, Δ68Hz).

• Biomaterials and Biomechanics in Bioengineering
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• 제1권3호
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• pp.117-130
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• 2014

This paper presents a study on the influence of different thermo-mechanical processing (TMP) parameters on some required properties such as micro-hardness and Young's modulus of a novel near ${\beta}$ alloy Ti-20.6Nb-13.6Zr-0.5V (TNZV). The TMP scheme comprises of hot working above and below ${\beta}$ phase, solutionizing treatment above and below ${\beta}$ phase coupled with different cooling rates. Factorial design of experiment is used to systematically collect data for micro-hardness and Young's modulus. Validity of assumptions related to the collected data is checked through several diagnostic tests. The analysis of variance (ANOVA) is used to determine the significance of the main and interaction effects. Finally, optimization of the TMP process parameters is also done to achieve optimum values of the micro-hardness and Young's modulus.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2002년도 추계학술대회 논문집 Vol.15
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• pp.326-329
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• 2002

In this study, to develop the low temperature sintering ceramics for multilayer piezoelectric transformer, $0.02Pb(Sb_{1/2}Nb_{1/2})O_{3}-0.13Pb(Ni_{1/3}Nb_{2/3}O_3-0.85Pb(Zr,Ti)O_{3}$ system ceramics were manufactured with the variations of sintering temperature between 1,090 and $1240^{\circ}C$ and its dielectric and piezoelectric characteristics were investigated. With increasing the sintering temperature, electromechanical coupling factor (kp) and mechanical quality factor(Qm) were decreased. At $1,180^{\circ}C$ sintered specimen showed maximum value of 0.535 electromechanical coupling factor (kp). On the other hand,. The specimen sintered at $1,180^{\circ}C$ showed the maximum value of ${\varepsilon}r$=1,571, Qm=1,181 respectively.

• 한국분말재료학회지
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• 제12권6호
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• pp.406-412
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• 2005

This work is to present a new synthesis of metallic glass (MG)/metallic glass (MG) composites using gas atomization and spark plasma sintering (SPS) processes. The MG powders of $Cu_{54}Ni_6Zr_{22}Ti_{18}$ (CuA) and $Ni_{59}Zr_{15}Ti_{13}Nb_7Si_3Sn_2Al_1$(NiA) as atomized consist of fully amorphous phases and present a different thermal behavior; $T_g$ (glass transition temperature) and $T_x$ (crystallization temperature) are 716K and 765K for the Cu base powder, but 836K and 890K for the Ni base ones, respectively. SPS process was used to consolidate the mixture of each amorphous powder, being $CuA/10\%NiA\;and\;NiA/10\%CuA$ in weight. The resultant phases were Cu crystalline dispersed NiA matrix composites as well as NiA phase dispersed CuA matrix composites, depending on the SPS temperatures. Effect of the second phases embedded in the MG matrix was discussed on the micro-structure and mechanical properties.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2005년도 추계학술대회 논문집 Vol.18
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• pp.212-213
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• 2005

In this study, in order to develop low temperature sintering piezoelectric actuator, $Pb_{0.985}Bi_{0.01}(Mg_{1/2}W_{1/2})_{0.03}(Ni_{1/3}Nb_{2/3})_{0.13}(Zr_{0.50},Ti_{0.50})_{0.84}$ (PMW-PNN-PZT) ceramic systems were fabricated using $CaCO_3-Li_2CO_3$, sintering aid through a post-annealing process. The sinterability of PMW-PNN-PZT ceranics was remarkably enhanced by liquid phase sintering of $CaCO_3$ and $Li_2CO_3$. But, it was confimed form the X-ray diffraction pattern that the secondary phase along grain boundaries, deteriorated the piezoelectric properties. The secondary phase along grain boundaries was significantly removed by annealing after sintering. The 0.2wt% $Li_2CO_3$-0.25wt% $CaCO_3$-added PMW-PNN-PZT ceramics post-annealed at 900$^{\circ}C$ for 90min exhibited the excellent electromechanical coupling factor($k_p$) of 63.3% and piezoelectric constant($d_{33}$) of 452pC/N, respectively, for multilayer piezoelectricactuatorapplication.

• 한국전기전자재료학회논문지
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• 제13권4호
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• pp.286-293
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• 2000

In this paper we investigated the structural dielectric and piezoelectric properties of 0.03Pb(Sb$\_$1/2//Nb$\_$1/2/)-0.97Pb(Zr$\_$0.495//Ti$\_$0.505/)O$_3$+0.5 wt% excess PbO + wt% MnO(X=0, 0.1, 0.3, 0.5, 0.7) ceramics to develop the high-power piezoelectric transformer. The piezoelectric transformers with dimension of 27.5$\times$27.5$\times$2.5［mm$^3$］were fabricated and their electrical properties were measured. Maxima of piezoelectric properties such as electro-mechanical coupling factor of 0.534 and mechanical quality factor of 1487 were obtained for the PSN-PZT with 0.3wt% MnO. voltage step-up ratios of piezoelectric transformers at 500［Ω］and no load were 0.78, 12.82, respectively. The maximum efficiency of piezoelectric transformer was 98.6% at 800［Ω］. While the 14W fluorescent lamp were driven by the piezoelectric transformer for more than 20［min］, increment of temperature in the piezoelectric transformer was 7［$\^{C}$］.

• 한국전기전자재료학회논문지
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• 제13권11호
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• pp.921-925
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• 2000

Characteristics of Pb(Mg, Nb)O$_3$-Pb(Zr, Ti)O$_3$system thick films fabricated by a screen printing method were investigated. The buffer layer were coated with various thickness of Ag-Pd by screen printing to investigate the effect as a diffusion barrier and deposited Pt as a electrode by sputtering on Ag-Pb layer. The printed thick films were burned out at 650$\^{C}$ and sintered at 950$\^{C}$ in O$_2$condition for each 20, 60min after printing with 350mesh screen. The thickness of piezoelectric thick film was 15∼20㎛ and Ag-Pb layer acted as a diffusion barrier above 3㎛ thickness. The PMN-PZT thick films were screen printed on Pt/Ag-Pb(6m) and sintered by 2nd step (650$\^{C}$/20min and 950$\^{C}$/1h) using paste mixed PMN-PZT and binder in the ratio of 70:30, and the remnant polarization of thick film was 9.1$\mu$C/㎠ in this conditions.