• 한국재료학회지
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• 제11권6호
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• pp.498-501
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• 2001

0.9Pb($Mg_{1/3}Nb_{2/3}$)$O_3$-0.1Pb$TiO_3$계 완화형 강유전체에서 MnO$_2$ 첨가가 압전물성에 미치는 영향을 강유전성이 우세한 온도영역인 -40~3$0^{\circ}C$의 온도범위에 걸쳐 조사하였다. MnO$_2$ 첨가에 의한 효과를 유전특성, 압전특성, 전계유기 변형특성 등의 영역에서 고찰하였다 MnO$_2$ 첨가량이 증가할수록 유전성 및 압전성은 hard piezoelectric의 경향을 나타내었다. 이러한 실험적 고찰로부터 첨가된 Mn은 강유전 도메인 분역을 고정하는 역할을 하는 것으로 제안되었다.

• 센서학회지
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• 제8권6호
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• pp.476-480
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• 1999

PLD 법을 이용하여 PbSe 박막을 p-Si(100) 기판 위에 성장시켰다. 성장온도에 따른 박막의 결정구조를 조사하기 위하여 기판온도를 RT${\sim}400^{\circ}C$로 변화시키면서 박막을 제작하였다. 여러 기판온도에서 제작한 PbSe 박막의 XRD 패턴과 PbSe(200) rocking curve의 반치폭(FWHM)을 분석한 결과, 성장온도 $200^{\circ}C$에서 제작한 박막이 가장 양호한 결정성을 나타냈다. 또한 AFM으로 관찰한 PbSe 박막의 표면형태도 $200^{\circ}C$에서 성장시킨 박막의 표면입자들이 가장 규칙적인 배열을 보였다. Hall 측정결과, PbSe 박막은 n-type 반도체임을 알 수 있었고, 전류-전압 특성 곡선은 전형적인 p-n junction 현상을 나타냈다. 또한 n-type 반도체인 PbSe 박막의 전기전도도는 일반적인 반도체의 값보다 약간 큰 것으로 확인되었다.

• 한국표면공학회지
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• 제40권5호
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• pp.225-233
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• 2007

Effects of alloying elements on the corrosion layer formation of Pb-grid/active materials interface has been researched for improvement of corrosion resistance of Pb-Ca alloy. For this research, various amounts of alloying elements such as Sn, Ag and Ba were added to the Pb-Ca alloys and investigated their corrosion behaviors. Batteries fabricated by using these alloys as cathode grids were subjected to life cycle test. Overcharge life cycle test was carried out at $75^{\circ}C$, 4.5 A, for 110 hrs. with KS standard (KSC 8504). And then, after keeping the battery with open circuit state for 48 hr, discharge was carried out at 300A for 30 sec. Corrosion morphology and interface between Pb-grid and active materials were investigated by using ICP, SEM, WDX, and LPM. Corrosion layer of Pb-Ca alloy got thicken with increasing Ca content. For Pb-Ca-Sn alloy, thickness of corrosion layer decreased as Sn and Ag content increased gradually. In case of Pb-Ca-Sn-Ba alloy, thickness of corrosion layer decreased up to 0.02 wt% Ba addition, whereas, it was not changed in case of above 0.02 wt% Ba addition.

• Journal of Welding and Joining
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• 제16권3호
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• pp.148-156
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• 1998

The purpose of this study is to investigate the characteristics of Pb-Free Sn-2%Ag-Bi solder alloys. The solder alloys used in this study is Sn-2%Ag-(3,5,7,9%) Bi It is examined that their properties such as melting range, wettability, microstructure, microhardness, and tensile property. The addition of Bi(3,5,7,9%) lowered the melting point of the solder and the melting range was 196~203$^{\circ}C$. The wettability of the solder as equal to that of Sn-37% Pb solder. The morphology of structure did not change largely by addition of Bi. But the structure of cellular dendrite of linear type displayed. The tensile strength of the solder was superior to that of Sn-37%Pb solder. But the elongation was inferior to that of Sn-37%Pb solder. The hardness of Sn-2%Ag solder was tow times and that of Sn-2%Ag-Bi solder was three times of that in Sn-37%Pb solder. But the effect of increment of Bi content did not change largely.

• 한국세라믹학회지
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• 제27권2호
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• pp.187-194
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• 1990

Effects of MnO2 addition ranged from 0.0wt% to 5.0wt% on the microstructure and dielectric and piezoelectric properties of the Pb(Zr0.52 Ti0.48)O3 Ceramics have been investigated. The solubility limit of MnO2 in Pb(Zr0.52 Ti0.48)O3 is about 0.5wt%, and MnO2 as a valence state of Mn3+ is substituted for (Zr, Ti) lattice site in PZT solid-solution. The addition of MnO2 up to 0.5wt% in Pb(Zr0.52 Ti0.48)O3 brings increase of density, but decreased of grain size and tetragonality. Dielectric constant slightly decreases, but both coupling factor(Kp) and mechanical quality factor(Qm) increase with the addition of MnO2. However, excess amount of MnO2 addition more than 0.75wt% results in rapid decrease of resistance. Dielectric constant and tan $\delta$ increase due to the second phase and inhomogeneous Mn distribution.

• 한국세라믹학회지
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• 제34권1호
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• pp.31-36
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• 1997

유전율이 높고 온도안정성이우수하다고 알려져 있는 Pb(Mg1/3Nb2/3)O3-PbTiO3-Pb(Mg1/2W1/2)O3 계 세라믹스를 산화물혼합법 및 precursor방법으로 제조함에 있어 과잉 MgO의 첨가에 따른 미세구조와 유전특성의 변화에 대하여 조사하였다. MgO를 5mol%이상 과잉첨가하여 100$0^{\circ}C$에 소결한 시편의 유전율은 5000이상이고, -55$^{\circ}C$에서 1$25^{\circ}C$범위에서 변화율은 +25%에서 -5$0^{\circ}C$ 정도를 나타냈다. XRD 분석결과 perovskite상과 Pb2WO5 결정이 주된상이었으며, 소결온도 및 MgO 첨가량이 증가함에 따라 cubic pyrochlore상인 Pb3Nb4O13와 PbWO4는 감소하였다. SEM에 의한 미세구조의 관찰에서 MgO첨가량이 증가함에 따라 결정성장이 촉진되는 것을 알 수 있었으며 이것이 소결온도 증가에 따른 pyrochlore상의 감소와 함께 유전율을 증가시키는 원인이었다. BSE관찰에서 화학성분 분포의 불균일성이 나타났으며, 각각의 소결온도에서 생성되는 결정상과 함께 유전율의 온도의존성을 완만하게 만드는 원인임을 알 수 있었다.

• 한국전기전자재료학회논문지
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• 제16권8호
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• pp.676-680
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• 2003

In this study, to develop the low temperature sintering ceramics for piezoelectric transformer, PSN-PNN-PZT system ceramics were manufactured as a function of V$_2$O$_{5}$ addition, that is the low melting point oxide. Its dielectric and piezoelectric characteristics were investigated. With increasing the amount of V$_2$O$_{5}$ addition, electromechanical coupling factor(kp) and mechanical quality factor(Qm) were decreased. For piezoelectric transformer application, the 0.1wt% V$_2$O$_{5}$ added specimen sintered at 1,00$0^{\circ}C$ showed the proper value of $\varepsilon$r=1,590, kp=0.51 and Qm=748.m=748.

• Bulletin of the Korean Chemical Society
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• 제25권2호
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• pp.233-236
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• 2004

Total impurity analysis of a primary standard solution is one of the essential procedures to determine an accurate concentration of the standard solution by the gravimetry. Bi impurity is determined in Pb standard solutions by inductively coupled plasma mass spectrometry (ICP-MS). The direct nebulization of the Pb standard solution produces a significant amount of the Pb matrix-induced molecular ions which give rise to a serious spectral interference to the Bi determination. In order to avoid the spectral interference from the interferent $^{208}PbH^+$, the hydride generation method is employed for the matrix separation. The Bi hydride vapor is generated by reaction of the sample solution with 1% sodium borohydride solution. The vapor is then directed by argon carrier gas into the ICP after separation from the mixture solution in a liquid-gas separator made of a polytetrafluoroethylene membrane tube. The presence of 1000 ${\mu}$g/mL Pb matrix caused reduction of the bismuthine generation efficiency by about 40%. The standard addition method is used to overcome the chemical interference from the Pb matrix. Optimum conditions are investigated for the hydride-generation ICPMS. The detection limit of this method is 0.5 pg/mL for the sample solutions containing 1000 ${\mu}$g/mL Pb matrix.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1991년도 추계학술대회 논문집 학회본부
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• pp.269-273
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• 1991

High Tc oxide superconductor with a Tc above 100 K has been successfully prepared by solid state reaction method in added-Pb BiSrCaCuO system. As compared with 123 compound, the formation reaction of the high Tc requires long time heat treatment. It is due to the transformation from the low Tc phase to high Tc phase. The sintering just below the melting point of the calcined powder mixture is effective on the formation of the high Tc phase in BiSrCaCuO system to be added with Pb. The growth of the high Tc superconducting phase has a thin plate shape, which is characterized by the c parameter of 37${\AA}$. The formation kinetics is also investigated in the samples with different Bi/Pb ratio and the 30% Pb addition is most preferable for the formation of the high Tc phase. The formation of the high Tc phases is delayed by the excessive addition of Pb. The lattice parameter(c) of the unit cell(both the low and high Tc phases) is increased with increase of Pb.

• 한국세라믹학회지
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• 제24권3호
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• pp.263-269
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• 1987

It is investigated that the determination of the correlation between the change of microstructure and electrical properties. Yttria is added to the compositiojn of rhombohedral region in Pb(Mg1/3Nb2./3)O3-PbTiO3-PbZrO3 ternary system. Average grian size, lattice parameters and distribution of yttrium are characterized by XRD, SEM and EDS. Electrical properties are determined by measurement of Curie temperature, piezoelectric properties and hysteresis loops. The results are as follows; 1. Both lattice parameters, a and ${\alpha}$, are changed by addition of yttria to the composition of rhomboheadral region in Pb(Mg1/3Nb2./3)O3-PbTiO3-PbZrO3 ternary system and Curie temperature is proportional to the values at (90-${\alpha}$).