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  • Title/Summary/Keyword: Ti-Zr-Ni

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Phase Transition of TiO2 prepared by HPPLT (저온균일침전법에 의해 제조된 TiO2의 상변화)

  • Hwang, Du-Seon;Lee, Nam-Hui;Lee, Gang;Kim, Seon-Jae
    • Proceedings of the Materials Research Society of Korea Conference
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    • 2003.03a
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    • pp.208-208
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    • 2003
  • 저온균일침전법(HPPLT)으로 제조된 TiO2나노분말은 100C이하의 온도에서 rutile상을 얻을 수 있다. 또한, rutile에서 anatase로의 상변화는 합성시간, 가열속도, 반응온도 그리고 음이온 첨가에 의해 일어난다고 보고되어졌지만, 금속양이온들에 의한 상변화는 알려진 바가 없다. 따라서, 다양한 양이온을 첨가하여 저온균일침전법에서 TiO2의 상변화가 어떻게 일어나는지를 조사하였다. 출발원료인 TIC14를 사용하여 가수분해하여 0.67M의 TiOCl2을 얻었다. 얻어진 TiOCl2 수용액에 각각 0.01M의 금속염화물(ZrOCl2, NiCl2, CuCl2, FeCl3, AlCl3 그리고 NbCl5)을 첨가한 후 반응기에 넣고 100C에서 4시간동안 가열하였다 가열한 후 얻어진 침전물에 NaOH 수용액을 이용하여 PH 7-8로 중화한 후 증류수로 Cl이온이 제거될 때까지 충분히 세척하였다. 세척된 침전물을 105C에서 24h동안 건조하여 분말을 얻었고, rutile에서 anatase로의 상변화특성을 관찰하기 위하여 XRD, SEM, TEM, ICP 분석을 실시하였다.

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Spark Plasma Sintering of the Ductile Cu-Gas-atomized Ni Bulk Metallic Glass Composite Powders (연질 Cu 분말-가스분무 Ni계 벌크 비정질 복합분말의 방전플라즈마 소결에 관한 연구)

  • Kim, Jin-Chun;Kim, Yong-Jin;Kim, Byoung-Kee;Kim, Ji-Soon
    • Journal of Powder Materials
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    • v.13 no.5 s.58
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    • pp.351-359
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    • 2006
  • Ni based(Ni57Zr20Ti18Si2Sn3) bulk metallic glass(BMG) powders were produced by a gas atomization process, and ductile Cu powders were mixed using a spray drying process. The Ni-based amorphous powder and Cu mixed Ni composite powders were compacted by a spark plasma sintering (SPS) processes into cylindrical shape. The relative density varied with the used SPS mold materials such as graphite, hardened steel and WC-Co hard metal. The relative density increased from 87% to 98% when the sintering temperature increased up to 460C in the WC-Co hard metal mold.

Dielectric and Piezoelectric Properties of PSS-PT-PZ Ceramics with the Addition of Dopant (불순물 첨가에 따른 PSS-PT-PZ 세라믹의 유전 및 압전특성)

  • Kang, Jeong-Min;Lee, Sung-Gap;Lee, Sang-Heon;Bae, Seon-Gi;Lee, Young-Hie
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 2003.11a
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    • pp.296-299
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    • 2003
  • In this paper, 0.10Pb(Sb1/2Sn1/2)O30.25PbTiO30.65PbZrO3 ceramics were fabricated by the mixed-oxide method. The sintering temperature and time were 1230C and 2[hr], respectively. The structural, dielectric and piezoelectric properties with addition of NiO were studied. The crystal structure of a specimen was rhombohedral. As a result of SEM, the average grain size were decreased with increasing the contents of NiO. But the grains of the specimens doped with 0.4wt% NiO were increased, due to deposits of excess NiO at grain boundaries in the liquid phase. Relative dielectric constant and dielectric loss of the specimen doped with 0.1wt% NiO were 701 and 0.026, respectively.

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A Study on Viscous Flow of the Zr-based Bulk Metallic Glass in an Undercooled Liquid State (Zr계 벌크 비정질 합금의 과냉 액상 영역에서의 점성 유동 현상 연구)

  • Lee K. S.;Ha T. K.;Chang Y. W.
    • Proceedings of the Korean Society for Technology of Plasticity Conference
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    • 2004.05a
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    • pp.265-268
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    • 2004
  • In this present study, mechanical properties of the Zr-Ti-Cu-Ni-Be bulk metallic glass are characterized by compression test over a wide range of temperatures and strain rates. Three different types of deformation behavior have been identified as a result, viz., Newtonian viscous flow, non-Newtonian flow and brittle fracture without plastic deformation. A transition state theory is applicable fur the flow stress - strain rate curve that contains the transition from Newtonian to non-Newtonian flow. Based on the relationship between viscosity and strain rate within undercooled liquid state, we can easily obtain the experimental deformation map and suggest the boundaries among different deformation behavior of this alloy.

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A Study on the Relationship between Deformation Mode and Extrusion Properties for Zr-based Bulk Metallic Glass (Zr계 벌크 비정질 합금의 변형 모드와 압출 특성의 상관 관계에 관한 연구)

  • Lee K. S.;Chang Y. W.
    • Proceedings of the Korean Society for Technology of Plasticity Conference
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    • 2004.10a
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    • pp.199-202
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    • 2004
  • In this present study, an attempt was made to determine the deformation mode of the Zr-Ti-Cu-Ni-Be bulk metallic glass by compression test over a wide range of temperatures and strain rates. From the results, empirical deformation map could be constructed including the boundaries of different deformation modes. Considering power dissipation map and instability map developed on the basis of the Dynamic Materials Model (DMM), the processing map for extrusion could also be constructed. In addition, the macroscopic formability of this BMG alloy has also been examined through the extrusion in laboratory scale within undercooled liquid state. From the results of macroscopic extrusion formability, both deformation map and processing map present good criteria to determine optimal forming conditions.

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Electric properties of PZN-PNN-PT-PZ piezoelectric ceramics prepared by molten salt method (용융염 합성법으로 제조한 PZN-PNN-PT-PZ계 압전세라믹스의 전기적 특성)

  • 어수해;이기태
    • Electrical & Electronic Materials
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    • v.9 no.4
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    • pp.351-356
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    • 1996
  • The quartemary system ceramics 0.5[xPb(Zn13/Nb23/)O3-(1-x)Pb(Ni13/Nb23/)O3]-0.5[yPbTiO3-(1-y) PbZrO3 for piezoelectric actuators were prepared bv the were added to the raw materials up to 5 mole. Sintering temperature was varied form 1000.deg. C to 1200.deg. C. Sintering characteristrics, dielectric and piezoelectric properties were then investigated. Piezoelectric properties of sample prepared by the molten salt method were improved compared to those prepared by the conventional method. Addition of PZN shifted morphotropic phase boundary to more Zr-rich composition and decreased the piezoelectric properties.

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Development and Application of Engineering Ceramics by Reaction Sintering (액상 반응소결에 의한 세라믹 구조재료의 개발 및 응용)

  • 한인섭;우상국;배강;홍기석;이기성;서두원
    • Proceedings of the KAIS Fall Conference
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    • 2000.10a
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    • pp.42-42
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    • 2000
  • 반응소결 탄화규소는 소결체 내에 잔존 실리콘이 남아 있어 고온강도의 감소를 초래하는 단점이 있어 고온 구조재료로서의 사용이 제한되어 왔다. 따라서 이러한 문제점을 해결하기 위한 방법으로 Si 단독으로 용응침투시키는 대신 Si-MoSi₂를 침투시키는 방법이 시도되고 있으며, 이외에도 TiC 성형체에 Co, Ni 등의 금속, ZrB₂ 성형체에 Zr 금속 등을 용융, 침투시켜 성능향상을 유도하는 연구가 진행되고 있다. 본 연구에서는 반응소결에 대한 기본이론과 응용분야, 반응소결 비산화물계 세라믹스의 제조공정 및 이들 소결체의 미세구조와 기계적 특성 등을 소개하고자 한다.

The Characteristics of PbTiO3PbZrO3Pb(Ni1/3Nb2/3)O3 Piezoelectric Thin Film Made by Sol-Gel Method (Sol-Gel 법으로 제작한 PbTiO3PbZrO3Pb(Ni1/3Nb2/3)O3 압전박막의 특성)

  • Yoon, Wha-Joong;Lim, Moo-Yeol;Koo, Kyung-Wan
    • Journal of Sensor Science and Technology
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    • v.4 no.4
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    • pp.75-80
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    • 1995
  • In order to fabricate the piezoelectric thin film of the PZT-PNN ternary compound, the metal alkoxides were used as starting materials. The electrical and crystalline properties of the thin film were evaluated. The X- RD study shows that the crystallization of the film is optimized at 550C of sintering temperature. According to the D-E hysterisis curve, the coercive field is 28.8 kV /cm, and the remanent polariztion is 18.3μC/cm2. The break down voltages of the thin films are 76.027.0MV/m. When the sintering temperature is raised, the break down voltage is lowered. As a result of measuring the C-V characteristic curve of the ternary compound piezoelectric thin film, the relative dielectric constants are 406 for the composition (50:40:10), 1084 for the composition (50:30:20), 723 for the composition (45:35:20) and 316 for the composition (40:40:20).

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Electorchemical Reduction Behavior of Aliphatic Acetylenic Alcohol (Aliphatic Acetylenic Alcohol의 電極反應過程)

  • Kim Won Taik;Kim, Jin Il;Kwak Tai-Young;Lee Ju-Seong
    • Journal of the Korean Chemical Society
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    • v.23 no.3
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    • pp.180-185
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    • 1979
  • Electrochemical reduction behavior from 2-butyne-1, 4-diol (BID) to 2-butene-1,4-diol (BED) by the use of various cathodes, such as Ti, Zr, Ni, Pt, Cu, Ag, Au, Zn, Hg, Pb and graphite has been studied. It has been found that cathodic polarization curve with metal of IB subgroup such as Cu, Ag and Au consisted of one wave in BID-alkaline solution, whereas it was not formed any wave in BED solution. Therefore, it was found that the cathode which was the most suitable in order to proceed in this reaction was Cu, Ag and Au. At cyclic voltammetry using a silver cathode in BID-alkaline solution, the current of the peak was proportional to square root of the sweep rate of potential and also proportional to concentration of BID. Activation energy was calculated for 3.75 kcal/mole from the plot of log Il vs. 1/T. Consequently, the reduction current of BID with a silver cathode in alkaline solution was found the diffusion current.

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Seasonal Variation and Statistical Analysis of Particulate Pollutants in Urban Air (도시대기립자상물질중 오염성분의 계절적 변동 및 통계적 해석)

  • 이승일
    • Journal of environmental and Sanitary engineering
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    • v.9 no.2
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    • pp.8-23
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    • 1994
  • During the period from Mar., 1991 to Feb., 1992 66 tSP samples were collected by Hi volume air sampler at 1 sampling site in Seoul and the amount of concentration of 21 components(SO42, NO3, NH4+, Cl, Al, Ba, Ca, Cd, Cr, Cu, Fe, It Mg, Mn, Na, Ni, Pt Si, Ti, Zn, Zr ) were measured. And monthly and seasonal variation were surveyed and the principal component analysis( PCA ) were carried out with respect to these amount of pollutants, minimum of visibility and radiation on a horizontal surface. The total amount of soluble ion in water was high in order o(SO42> NO3> N%'>Cl and metal ion was high in order of Na> Ca>Si> Fe> Al> K> Mg> Zn> Pb> Cu>Ti> Mn > Ba> Cr> Zr> Ni> Cd. There was Seasonal variation in concentration for SO42, NH4+, Cl, Na, Al, Ca, Bt Mg, Fe and Si. It was assumed that the components of the highest concentration on April were depend on yellow sand and the frequency of wind velocity and direction. As the results of PCA, the amount of pollution components was able to characterized with two principal components(Z1, Z2 ). The first principal components Z1 was considered to be a factor indicating the pollutants originated from natural generation and The second principal components Z2 was considered to be a factor indicating the pollutants originated from human work. The monthly concentration of pollutants in ISP, minimum of visibility and radiation on a horizontal surface was possible to evaluate by the use of these two principal components Z1 and Z2 .

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