• Title/Summary/Keyword: Ti-Zr-Ni

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Piezoelectric and Dielectric Characteristics of Low Temperature Sintering Pb(Mn1/3Nb2/3)O3-Pb(Ni1/3Nb2/3)O3-Pb(Zr1/2Ti1/2)O3 Ceramics according toPb(Ni1/3Nb2/3)O3 Substitution (Pb(Ni1/3Nb2/3)O3 치환에 따른 저온소결 Pb(Mn1/3Nb2/3)O3-Pb(Ni1/3Nb2/3)O3-Pb(Zr1/2Ti1/2)O3 세라믹스의 압전 및 유전 특성)

  • Yoo Ju-Hyun;Lee Sang-Ho;Paik Dong-Soo
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
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    • v.19 no.1
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    • pp.35-39
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    • 2006
  • In this study, in order to develop the multilayer piezoelectric actuator and ultrasonic resonator, PMN-PNN-PZT ceramics were fabricated by sintering with Li2CO3Na2CO3Li2CO3Na2CO3 as sintering aids at 950C950C and their piezoelectric and dielectric characteristics were investigated as a function of PNN substitution. With increasing PNN substitution, dielectric constant(ϵrϵr), electromechanical coupling factor(kp), and piezoelectric d constant(d33d33) were increased to 12mol%12mol% PNN substitution and then showed a tendency to decrease rapidly With increasing PNN substitution, crystal structure changed from tetragonal to rhombohedral at 12mol%12mol% PNN substitution and then secondary phase was appeared and its intensity was increased. At the 12mol%12mol% PNN substituted PMN-PZT composition ceramic sintered at 950C950C, density, kp, d33d33 and Qm showed the optimum value of 7.79g/cm37.79g/cm3, 0.599, 419 pC/N, and 894, respectively for multilayer piezoelectric actuator application.

Geochemical Composition of Volcanic Ash from Historical Eruptions of Mt. Baekdu, Korea (역사시대에 분화한 백두산 화산재의 화학 성분)

  • Yun, Sung-Hyo;Koh, Jeon Seon;Chang, Cheolwoo
    • The Journal of the Petrological Society of Korea
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    • v.27 no.1
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    • pp.37-47
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    • 2018
  • Volcanic ash samples of historical eruptions from Mt. Baekdu were analyzed for major oxides, trace and rare earth elements by a variety of analytical techniques. The results indicate that the ashes consist of approximately 58.8~71.1 wt.% SiO2SiO2, 9.6~16.8 wt.% Al2O3Al2O3, 4.5~6.9 wt.% Fe2O3tFe2O3t, 0.1~1.7 wt.% MgO, 0.3~1.6 wt.% CaO, 5.2~6.3 wt.% Na2ONa2O, 4.3~5.9 wt.% K2OK2O and less than 1.2 wt.% TiO2TiO2. Thirty two trace metals including Ba, Cu, Cr. Co, Ni, Sr, V, Zn, and Zr were analyzed. The ashes can be divided two groups: group A(1 ka Millennium pumice, 1668 and 1903_1903 pumice) and group B(1702 pumice) according to the relative enrichment of HREEs. The abundances of heavy metals such as Cu, Co, Mn, and Zn were relatively low. As compared to the Sakurajima volcanic ash, Baekdusan volcanic ash has low concentrations of Y, Nb, Pb, U, Sc, V, Ni and Cu and high concentrations of Zr, Ba, Hf, Cr, Co, Zn and rare-earth (except Eu).

Flow Stress and Deformation Behavior of Zr-based Bulk Metallic Glass Composite in Supercooled Liquid Region (Zr계 비정질 복상 합금의 과냉 액상 영역에서의 유동 음력과 변형거동)

  • Jun, H.J.;Lee, K.S.;Chang, Y.W.
    • Proceedings of the Korean Society for Technology of Plasticity Conference
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    • 2006.05a
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    • pp.417-420
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    • 2006
  • The composition and structure of dendrite phase within Zr76.11Ti4.20Cu4.51Ni3.16Be1.49Nb10.53Zr76.11Ti4.20Cu4.51Ni3.16Be1.49Nb10.53 bulk metallic glass (BMG) were confirmed by using an EPMA, XRD and TEM, respectively. The chief elements of dendrite phase were Zr-Ti-Nb and had a BCC structure. The thermal properties of this BMG have been then subsequently investigated by using a differential scanning calorimeter (DSC). The glass transition and crystallization onset temperatures were determined as 339.7C339.7C and 375.8C375.8C for this alloy, respectively. Mechanical properties have also been examined by conducting a series of uniaxial compression tests at various temperatures within supercooled liquid region under the strain rates between 104/s104/s and 3×102/s3×102/s. The deformation behavior of BMG composite within supercooled liquid region is similar to one of Vit-1 exhibiting amorphous single phase alloy. The flow stresses of BMG composite, however, are entirely higher than those of Vit-1 because dendrite phases are interfere with moving of atoms.

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Advanced SPS Systems and FGM Technolgy

  • Tokita, Masao
    • Proceedings of the Korean Powder Metallurgy Institute Conference
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    • 2000.04a
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    • pp.11-11
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    • 2000
  • Large-size ceramic/metal bulk FGMs have been fabricated on a recently developed and the world's largest Spark Plasma Sintering(SPS) systems, As a part of the development program for practical production processes and machines for FGMs by SPS, the processes, mechanical properties, dimensional size and shape effects, and production machine systems were investigated. In the past, ZrO2ZrO2/TiAI, ZrO2ZrO2/Ni, Al2O3Al2O3/Ti, WC/Co, WC/Co/Steel, A1/P, Polymide, Cu/Polymide, nano-composites, porous and other combinations of bulk FGMs have already been processed using SPS. However, most of the specimen sizes were small, in a range of 20 to 30mm in diameter. Recently disk-shape sintered compacts with diameters of 100 and 150 mm, and thickness of approximately 15 and 17 mm, ZrO2ZrO2(3Y)/ stainless steel FGMs were homogenous consolidated in a shorter sintering time, while maintaining high quality and repeatability by utilizing a temperature gradient sintering method. The SPS heating up and holding time totaled less than one hour. Therefore, the SPS process in expected to find increased use in the fabrication of large-size FGMs as a new industrial processing technology. This paper introduces SPS systems, the processing principles, features and the characteristies of ceramic/metal bulk FGM.

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A Study on the Electrode Charcteristics of the Fluornated AB22 Type Hydrogen Storage Alloys (불화 처리된 AB22계 수소저장합금의 전극특성에 관한 연구)

  • 박호영;이명호;조원일;조병래;이성래;주재백;윤경석
    • Journal of Surface Science and Engineering
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    • v.30 no.4
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    • pp.262-271
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    • 1997
  • Nickel-matal hydride(Ni-MH) batteries are receiving attention as non-pollunting. high performance rehargeable energy stoage system. The performance of Ni-Mh is significantly influenced by the hydrogen storage alloy materiels used as an anode material. Recently, having discharge capacities higher than the AB5AB5-type hydrogen storage alloys, the Zr-based AB2AB2-Type hydrogen storage alloys has remaining problems regarding cycle life and self-dischareg. These problems need to be solved by improvements in the alloy design and/or surface treatment. This work investiggates the effects the effects of surface property by fluorination on Zr0.7Ti0.3V0.4Mn0.4Ni1.2Zr0.7Ti0.3V0.4Mn0.4Ni1.2 composittion AB2AB2-Type hydrogen storage alloys. EPMA, SEM and AES techniques were used for surface analysis, and the crystal structure was characterized by constant current cycling test and potential sweep methods. Fluorination was found to be effective when La-was incorporated into the alloy, and has unique morphology, higher reactivity, and at the same time formed a protective film. Through, fluorination, the cycle life of an electrode was found to increase significantly, charge/discharge characteristics of the electrode the potential difference between the charge/discharge plateau, i.e polarization(overpotential)were improved.

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Dielectric and Piezoelectric Characteristics of 0.94(K0.5Na0.5)NbO3(K0.5Na0.5)NbO3-0.06Ba(Zr0.05Ti0.95)O3(Zr0.05Ti0.95)O3 Ceramics System According to the variations of sintering aids (소결조재 변화에 따른 0.94(K0.5Na0.5)NbO3(K0.5Na0.5)NbO3-0.06Ba(Zr0.05Ti0.95)O3(Zr0.05Ti0.95)O3 세라믹스의 유전 및 압전특성)

  • Seo, Byeong-Ho;Kim, Do-Hyung;Lee, Yu-Hyong;Yoo, Ju-Hyun
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 2008.11a
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    • pp.205-205
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    • 2008
  • PZT 세라믹은 우수한 유전 및 압전특성을 갖고 있어 변압기, 센서 및 엑츄에이터 등에 널리 응용되고 있다. 그러나, 우수한 특성에도 불구하고 PZT세라믹스의 소결시 PbO의 높은 유독성 및 휘발로 인하여 환경오염을 야기 시킨다. 그러므로 PbO로 구성된 세라믹을 대체하기 위한 우수한 압전특성을 가진 비납계 세라믹스 개발이 연구의 주류를 이루고 있다. 그 중 비납계 NKN와 BZT는 대체물질로 많이 관심을 받고 있다. 이는 일반적인 NKN조성은 우수한 압전성과 높은 큐리온도를 가지고 있을 뿐만 아니라, BZT조성의 Zr성분이 큐리온도를 낮추거나 유전특성을 졸게 하여 유전율 곡선을 완화하게 하는 특징이 있다. 하지만 NKN은 1140C1140C이상의 소결온도에서 K의 휘발특성으로 인해 소성 후에도 주변의 수분을 흡수하는 조해성이 발생하는 문제가 발생한다. 그래서 본 연구에서는 낮은 온도에서 NKN계 세라믹스의 밀도를 증가시킬 뿐만 아니라, 우수한 유전 및 압전특성을 갖는 세라믹스를 제조하고자 비납계 0.94(K0.5Na0.5)NbO30.06Ba(Zr0.05Ti0.95)O30.94(K0.5Na0.5)NbO30.06Ba(Zr0.05Ti0.95)O3 (NKN-BZT)의 조성을 사용하였고 소결조제로는 MnO2MnO2, NiO, Bi2O3Bi2O3, ZnO, Li2CO3Li2CO3, CuO등을 변화주어 유전 및 압전 특성을 알아보았다.

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Tensile Deformation Behavior of Zr-based Bulk Metallic Glass Composite with Different Strain Rate (Zr 계 벌크 비정질 복합재의 변형률 속도에 따른 인장 변형 거동)

  • Kim, Kyu-Sik;Kim, Ji-Sik;Huh, Hoon;Lee, Kee-Ahn
    • Proceedings of the Korean Society for Technology of Plasticity Conference
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    • 2009.05a
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    • pp.353-354
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    • 2009
  • Tensile deformation behavior with different strain rate was investigated. Zr56.2Ti13.8Nb5.0Cu6.9Ni5.6Be12.5Zr56.2Ti13.8Nb5.0Cu6.9Ni5.6Be12.5 (bulk metallic glass alloy possessed crystal phase which was called ββ-phase of dendrite shape, mean size of 2030μm2030μm and occupied 25% of the total volume) was used in this study. Maximum tensile strength was obtained as 1.74Gpa at strain rate of 102/s102/s and minimum strength was found to be 1.6GPa at 101/s101/s. And then, maximum plastic deformation occurred at the strain rate of 5×102/s5×102/s and represented 1.75%, though minimum plastic deformation showed 0%. In the specific range of strain rate, relatively higher plastic deformation and lower ultimate tensile strength were found with lots of shear bands. The fractographical observation after tensile test indicated that vein like pattern on the fracture surface was well developed especially in the above range of strain rate.

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The Effect of Thermo-Mechanical Treatment on Mechanical and Electrical Behavior of Cu Alloys (동합금의 가공열처리법에 의한 기계적·전기적 성질)

  • Kim, Hyung-Seok;Jeon, C.H.;Song, Gun;Kwun, S.I.
    • Journal of the Korean Society for Heat Treatment
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    • v.10 no.1
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    • pp.20-29
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    • 1997
  • Pure copper is widely used for base material for electrical and electronic parts because of its good electrical conductivity. However, it has such a low strength that various alloying elements are added to copper to increase its strength. Nevertheless, alloying elements which exist as solid solution elements in copper matrix severely reduce the electrical conductivity. The reduction of electrical conductivity can be minimized and the strengthening can be maximized by TMT(Thermo-Mechanical Treatment) in copper alloys. In this research, the effects of TMT on mechanical and electrical properties of Cu-Ni-Al-Si-P, Cu-Ni-Al-Si-P-Zr and Cu-Ni-Si-P-Ti alloys aged at various temperatures were investigated. The Cu alloy with Ti showed the hardness of Hv 225, electrical conductivity of 59.8%IACS, tensile strength of 572MPa and elongation of 6.4%.

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Piezoelectric Properties of 0.65Pb(Zr1-xTix)O3-0.35Pb(Zn1/6Ni1/6Nb2/3)O3 Ceramics and Their Application to Piezoelectric Energy Harvester (0.65Pb(Zr1-xTix)O3-0.35Pb(Zn1/6Ni1/6Nb2/3)O3 세라믹의 압전 특성 및 압전 에너지 하베스터 적용)

  • Jo, Sora;Kim, Daesu;Cho, Yuri;Son, Sin Joong;Kang, Hyung-Won;Nahm, Sahn;Han, Seung Ho
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
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    • v.31 no.4
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    • pp.216-220
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    • 2018
  • The piezoelectric properties of 0.65Pb(Zr1xTix)O30.35Pb(Zn1/6Ni1/6Nb2/3)O30.65Pb(Zr1xTix)O30.35Pb(Zn1/6Ni1/6Nb2/3)O3 (PZTxPZNNPZTxPZNN) ceramics with 0.530x0.5550.530x0.555 were investigated for application to piezoelectric energy harvesters. Although a morphotropic phase boundary (MPB) was found at approximately x = 0.545, the ceramic with the highest figure of merit (FOM) (d33×g33d33×g33) was observed at a composition of x = 0.540. Values of this figure of merit, d33×g33d33×g33, of 19.6pm2/N19.6pm2/N and 20.2pm2/N20.2pm2/N were obtained from PZT0.540PZNNPZT0.540PZNN ceramics sintered at 920C920C and 950C950C, respectively. A high output power of 937μW937μW and a high power density of 3.3mW/cm33.3mW/cm3 were obtained from unimorph-type piezoelectric energy harvesters fabricated using $PZT_{0.540}-PZNN$ ceramic sintered at 920C920C for 4h.

Selective Separation of 59/63Ni59/63Ni from Radioactive Wastes (방사성 폐기물 내 59/63Ni59/63Ni의 선택적 분리)

  • Lee Chang-Heon;Jung Kie-Chul;Choi Kwang-Soon;Jee Kwang-Yong;Kim Won-Ho
    • Proceedings of the Korean Radioactive Waste Society Conference
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    • 2005.06a
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    • pp.121-128
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    • 2005
  • A study on the selective separation of 99Tc,94Nb,55Fe,90Sr99Tc,94Nb,55Fe,90Sr and 59Ni(63Ni)59Ni(63Ni) from various radioactive wastes discharged from the nuclear power plants in Korea is being performed for use in their quantifications which are indispensible for the evaluation of the radionuclide inventory. Separation behaviour of Ce, Ca, Mg, Al, Cr, Ti, Mn and Cu recovered along with Ni during the separation of Re (as a surrogate of 99Tc99Tc), Nb, Fe and Sr by anion exchange and Sr-Spec extraction chromatography was investigated by cation exchange and Ni-Spec extraction chromatography using synthetic radioactive waste dissolved solutions containing matrix elements such as Re, Nb, Fe, Sr, Ni, B, Na, K, Ce, Co, Ca, Mg, Al, Zn, Cr, Pb, Cd, Mo, Mn, Cu, Zr, Ti and U. To purify the Ni fraction recovered and prepare a radionuclide source available for gas proportional counting, an application of the Ni precipitation procedure with dimethylglyoxime in the medium of ammonium citrate and tartaric acid solutions as a masking agent for co-existing metal ions was described in detail.

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