• Title/Summary/Keyword: Ti-Zr-Ni

Search Result 290, Processing Time 0.03 seconds

Synthesis of Cu-coated Ni-based Bulk Metallic Glass Powders by Gas Atomization and Spray Drying Process

  • Kim, Byoung-Kee;Kim, Yong-Jin;Kim, Jin-Chun
    • Proceedings of the Korean Powder Metallurgy Institute Conference
    • /
    • 2006.09b
    • /
    • pp.936-936
    • /
    • 2006
  • Bulk amorphous materials have been intensively studied to apply for various advanced industry fields due to their high mechanical, chemical and electrical properties. These materials have been produced by several techniques such as mechanical alloying, melt spinning and gas atomization, etc. Among them, the atomization is the most potential technique for commercialization due to high cooling rate during solidification of the melt and mass productivity. However, the amorphous powders still have some limitations because of their low ductility and toughness. Therefore, intensive efforts have to be carried out to increase the ductility and toughness. In this study, the Ni-based amorphous powder was produced by the gas atomization process. And in order to increase the ductile toughness, ductile Cu phase was coated on the Ni amorphous powder by spray drying process. The characteristics of the as-synthesis powders have been examined and briefly mentioned. The master alloy with Ni57Zr20Ti16Si2Sn3 was prepared by vacuum induction melting furnace with graphite crucible and mold. The atomization was conducted at 1450C under the vacuum of 102 torr. The gas pressure during atomization was varied from 35 to 50 bars. After making the Ni amorphous powders, the spray drying was processed to produce the Cu -coated Ni amorphous composite powder. The amorphous powder and Cu nitrate solution were mixed together with a small amount of binder and then it was sprayed at temperature of 130C and rotating speed of 15,000 R.P.M.

  • PDF

증착방법을 달리한 TiO2 박막의 표면처리에 따른 저항변화 특성 연구

  • Seong, Yong-Heon;Kim, Sang-Yeon;Do, Gi-Hun;Seo, Dong-Chan;Jo, Man-Ho;Go, Dae-Hong
    • Proceedings of the Korean Vacuum Society Conference
    • /
    • 2010.02a
    • /
    • pp.206-206
    • /
    • 2010
  • 정보화 기술이 급속히 발전함에 따라서 보다 많은 양의 data를 전송, 처리, 저장 하게 되면서 이를 처리 할 수 있는 대용량, 고속, 비휘발성의 차세대 메모리의 개발이 요구 되고 있다. 이 중 저항 변화 메모리(ReRAM)는 일반적으로 전이금속산화물을 이용한 MIM 구조로서 적당한 전기 신호를 가하면 저항이 높아서 전도되지 않는 상태(Off state)에서 저항이 낮아져 전도가 가능한 상태(On state)로 바뀌는 메모리 특성을 가진다. ReRAM은 비휘발성 메모리이며 종래의 비휘발성 기억소자인 Flash memory 보다 access time이 105배 이상 빠르며, 2~5V 이하의 낮은 전압에서 동작이 가능하다. 또한 구조가 간단하여 공정상의 결함을 현저히 줄일 수 있다는 점 등 많은 장점들이 있어서 Flash memory를 대체할 수 있는 유력한 후보로 여겨지고 있다. 저항 변화의 특징을 잘 나타내는 물질에는 TiO2, Al2O3, NiO2, HfO2, ZrO2등의 많은 전이금속산화물들이 있다. 본 연구에서는 Reactive DC-magnetron Sputtering 방법과 DC-magnetron sputter를 이용하여 Ti를 증착한 후 Oxidation 방법으로 각각 증착한 TiO2박막을 사용하여 저항변화특성을 관찰하였다. TiO2상부에 Atomic Layer Deposition (ALD)를 이용하여 HfO2 박막을 증착하여 표면처리를 하고, 또한 TiO2에 다른 전이 금속박막 층을 추가 증착하여 저항변화 특성에 접합한 조건을 찾는 연구를 진행하였다. 하부 전극과 상부 전극 물질로는 Si 100 wafer 위에 Pt 또는 TiN을 사용하였다. 저항변화 특성을 평가하기 위해 Agilent E5270B를 이용하여 current-voltage (I-V)를 측정하였다. X-ray Diffraction (XRD)를 이용하여 증착 된 전기금속 박막 물질의 결정성을 관찰했으며, Atomic Force Microscopy (AFM)을 이용하여 증착 된 샘플의 표면을 관찰했다. SEM과 TEM을 통해서는 sample의 미세구조를 확인 하였다.

  • PDF

UHV Materials (초고진공계재료)

  • 박동수
    • Proceedings of the Korean Vacuum Society Conference
    • /
    • 1998.02a
    • /
    • pp.24-24
    • /
    • 1998
  • 반도체장비를 포함하는 초고진공장비의 園훌化가 급속히 그리고 절실히 요구되고 있는 것이 현실정이다. 當面해서 실현할 국산진공장비의 대상은 廣範圍하다. 즉, 각종 진공 pump ( (rotary, dry, diffusion, cryo, ion, turbo melecular pump), 진공 chamber, 진공 line, gate valve 를 위 시 한 진공 V머ve, flange, gasket, fl않d야lU, mainpulater 퉁 진공 部品이 다. 진공계 의 핵심 은 適切하고 優良한 진공재료의 선태파 사용이다. 진공장비는 사용자가 원하는 진공도를 원하 는 시간 동안 륨空度를 유지해 주어야 한다. 진공재료 선태의 기준사항은:(1) 기체의 透過성 (2) 薰했훌 (3) 혔體放出특성 - -outgassing과 degassing- (4) 機械的 량훌度 (5) 온도 의존성 (6) 化學톡성 (7) 加I성 및 鎔接 성 (8) 課電특성 (9) 磁氣특성 (10) 高速함子 및 放射線 특성 (11) 經濟성 및 調達생 둥이 다. 우량한 초고진공계재료는 풍부하게 개발되어 왔고, 또 新材料들이 개발되고 있다. 여기에서는 주로 초고진공 내지는 극고진공계의 構造材料, 機能材料, 部品材料 일반파 몇가지 신재료의 특 성에 관해서 記述한다. M Mild SteeHSAE, 1112, 1010, 1020, 1022, etc)., S Stainless SteeHAlSI, 304, 304L, 310, 316, 321, 347): 구조재료, chamber, fl하1ges A Aluminum과 Alloys (1060, 1100, 2014, 4032, 6(뻐1): 구조재료, chamber, flanges, gaskets A AI, Al 떠loy는 SS에 代替하는 역 할올 시 작하고 있다. C Copper, Copper Alloys(C11α)0, C26800, C61400, Cl7200): 내장인자, gasket, cryopanel, tubing T Titanium, Ziriconium, Haf띠um 및 Alloys: 특히 Ti은 10n pump 용 getter material 이 외 에 U UHV,XHV용 chamber계로서 관심올 끌고 있다. N Nickel, Nickel Alloys (200, 204, 211, monel, nichrome): 부식 방지 , 전자장치 , 자기 장치 귀 금속(Ag, Au, Pt, Pd, Rh, Ir, Os, Ru): 보조부품, gasket, filament, coating, thermocouple, 접 합부위 T TiC, SiC, zrC, HfC, TaC 둥의 탄화물과, BN, TiN, AlN 동의 질화물, 붕화물이 둥장하고 었 다. 유리: Soda Lime, Borosilicate, Potash Soda Lead: View Port, Chamber envelope C Ceramics: AlZ03, BeO, MgO, zrOz, SiOz, MgOzSiOz, 3Alz032SiOz, ZtextsckhSiOz S상N4: e electrical, thermal insulators, crucibles, boats, single crystals, sepctr려 windows 저자는 최근 저자들이 발견한 Zr-Ti-Cu-Ni-Be amorphous alloys coated cham뾰r가 radiation p proof로 이용될 수 있는 사실을 점검하고 었다 .. Z.Y. Hua 들은 Cs3Sb를 새로운 photocathode 재료로 보고하고 있다.

  • PDF

Deformation and Fracture Behavior of Structural Bulk Amorphous Metal under Quasi-Static Compressive Loading (준정적 압축하에서 구조용 벌크 아몰퍼스 금속의 변형 및 파괴거동)

  • Shin, Hyung-Seop;Ko, Dong-Kyun;Oh, Sang-Yeob
    • Transactions of the Korean Society of Mechanical Engineers A
    • /
    • v.27 no.10
    • /
    • pp.1630-1635
    • /
    • 2003
  • The deformation and fracture behaviors of a bulk amorphous metal, Zr-based one (Zr_41.2/Ti_13.8/Cu_12.5/Ni_10/Be_22.5/: Vitreloy), were investigated over a strain rate range (7x10\^-4/~4 s\^-1/). The uniaxial compression test and the indentation test using 3mm-diameter WC balls were carried out under quasi-static loading conditions. As a result, at the uniaxial compressive state, the fracture stress of the material was very high (~1,700MPa) and the elastic strain limit was about 2%. The fracture strength showed a strain rate independent behavior up to 4 s\^-1/. Using indentation tests, the plastic deformation behavior of the Zr-based BAM up to a large strain value of 15% could be achieved, even though it was the deformation under locally constrained condition. The Meyer hardness of the Zr-based BAM measured by static indentation tests was about 5 GPa and it revealed negligible strain hardening behavior. At indented sites, the plastic indentation occurred forming a crater and well-developed multiple shear bands were generated around it along the direction of 45 degree when the indentation load exceeded 7kN. With increasing indentation load, shear bands became dense. The fracture surface of the specimen after uniaxial compressive tests showed vein-like pattern, typical morphology of many BAMs.

Petrology of Puu Oo lavas from the Big Island, Hawaii (하와이, 빅 아일랜드의 푸우오오 용암에 대한 암석학적 연구)

  • Kwon, Suk-Bom;Jang, Yun-Deuk;Park, Byeong-Jun;Kim, Yeong-Kyoo;Kim, Jung-Jin
    • The Journal of the Petrological Society of Korea
    • /
    • v.16 no.4
    • /
    • pp.217-232
    • /
    • 2007
  • The Puu Oo eruption in Hawaii since 1983 is one of the largest eruptions on Hawaii's volcanic history with prominent compositional variation (5.610.1wt. in MgO content). Although intense researches of Hawaiian eruption have been conducted for recent years, there is no up-to-date study on Puu Oo lavas that is erupting hot lavas today. in oder to obtain basic information on the geological characteristics of the eruption including any noticeable change in its petrological trend and magma dynamics, we applied several geological approaches such as field survey, systematic sampling, petrography, mineralogy, and geochemistry. Clinopyroxene and Plagioclase phenocrysts are rarely observed on the thin section, however Olivine crysts are much more obvious in the study area. It indicates that Puu Oo is early stage of magma differentiation. Variation diagram of whole rock composition shows that the elements such as TiO2,Al2O3,SiO2 and Na2O decrease with increasing MgO. In the trace element Sr, Y Zr and V versus K2O, P18, P19 samples are plotted in primitive area. Variations of the Ni contents during 20032006 may suggest a sudden change in magma composition probably caused by new magma injection.

Electrode characteristics of AB2 type hydrogen storage alloy modified by Cr, La addition and fluorination (AB2계 수소저장합금의 전극특성에 미치는 Cr, La 첨가 효과 및 표면 불화처리 효과)

  • Chang I.;Lee B. H.;Cho W. I.;Jang H.;Cho B. W.;Yun K. S.
    • Journal of the Korean Electrochemical Society
    • /
    • v.1 no.1
    • /
    • pp.45-51
    • /
    • 1998
  • [ AB2type ] alloy, one kind of hydrogen storage alloys used as an anode of Ni-MH batteries, has large discharge capacity but has remaining problems regarding initial activation, cycle life and self-discharge. This study investigates the effects of Cr-addition and fluorination after La-addition on Zr0.7Ti0.3V0.4Mn0.4Ni1.2, composition AB2type alloy. EPMA and SEM surface analysis techniques were used and the crystal structure was characterized by XRD analysis. In addition, electrodes were fabricated out of the alloys and characterized by constant current cycling test, electrochemical impedance spectroscopy and potentiodynamic polarization. Cr-addition was found to be effective to cycle life and self-discharge but ineffective to initial activation due to formation of stable oxide film on surface. Fluorination after La-addition to the alloys improved initial activation remarkably due to formation of highly reactive particles on surface.

Banded Iron Formations in Congo: A Review

  • Yarse Brodivier Mavoungou;Anthony Temidayo Bolarinwa;Noel Watha-Ndoudy;Georges Muhindo Kasay
    • Economic and Environmental Geology
    • /
    • v.56 no.6
    • /
    • pp.745-764
    • /
    • 2023
  • In the Republic of Congo, Banded iron formations (BIFs) occur in two areas: the Chaillu Massif and the Ivindo Basement Complex, which are segments of the Archean Congo craton outcropping in the northwestern and southwestern parts of the country. They show interesting potential with significant mineral resources reaching 2 Bt and grades up to 60% Fe. BIFs consist mostly of oxide-rich facies (hematite/magnetite), but carbonate-rich facies are also highlighted. They are found across the country within the similar geological sequences composed of amphibolites, gneisses and greenschists. The Post-Archean Australian Shale (PAAS)-normalized patterns of BIFs show enrichment in elements such as SiO2, Fe2O3, CaO, P2O5, Cr, Cu, Zn, Nb, Hf, U and depletion in TiO2, Al2O3, MgO, Na2O, K2O, Sc, Th, Ba, Zr, Rb, Ni, V. REE diagrams show slight light REEs (rare earth elements; LREEs) compared to heavy REEs (HREEs), and positive La and Eu anomalies. The lithological associations, as well as the very high (Eu/Eu*)SN ratios> 1.8 shown by the BIFs, suggest that they are related to Algoma-type BIFs. The positive correlations between Zr and TiO2, Al2O3, Hf suggest that the contamination comes mainly from felsic rocks, while the absence of correlations between MgO and Cr, Ni argues for negligeable contributions from mafic sources. Pr/Pr* vs. Ce/Ce* diagram indicates that the Congolese BIFs were formed in basins with redox heterogeneity, which varies from suboxic to anoxic and from oxic to anoxic conditions. They were formed through hydrothermal vents in the seawater, with relatively low proportions of detrital inputs derived from igneous sources through continental weathering. Some Congolese BIFs show high contents in Cr, Ni and Cu, which suggest that iron (Fe) and silicon (Si) have been leached through hydrothermal processes associated with submarine volcanism. We discussed their tectonic setting and depositional environment and proposed that they were deposited in extensional back-arc basins, which also recorded hydrothermal vent fluids.

Piezoelectric and Electro-induced Strain Properties of (Pb12x/3Bix)[(Ni1/3Nb2/3)0.4(Ti0.6Zr0.4)0.6]O3Ceramics with the Substitution of Bi2O3 (Bi2O3치환에 따른 (Pb12x/3Bix)[(Ni1/3Nb2/3)0.4(Ti0.6Zr0.4)0.6]O3 세라믹스의 압전 및 전계유기 왜형 특성)

  • 윤현상;정회승;임인호;윤광희;김준한;박창엽
    • Electrical & Electronic Materials
    • /
    • v.10 no.5
    • /
    • pp.434-439
    • /
    • 1997
  • It this paper, the piezoelectric and electro-induced strain properties of (P b12x/3/B ix )[N i13/N b23/)0.4( Ti0.6Z r0.4)0.6] O3ceramics (x=0, 0.005, 0.02) were investigated with the substitution of B i3+, and the feasibility of the application for bimorph actuator was evaluated by measuring the dynamic properties of the piezoelectric bimorph fabricated with above ceramics. Dielectric constant was enhanced with the increase of B i3+ substitution, and appeared the maximum value of 5032 at x=0.01 composition. Increasing the substitution of B i3+, the electromechanical coefficient( kp , k31 ) was increased up to the substitution of 0.5 mol% B i3+, showed the value of 0.656, 0.439, respectively. The piezoelectric constant( d33 d31 ) had the highest value of 344, 825 with the substitution of 0.5 mol% B i3+. The strain, generated by 60 Hz AC electric field, had the largest value of 1200(×106 Δ1/1) in the composition with the substitution of 0.5 mol% B i3+. The dynamic properties of the bimorph actuator, fabricated with the composition substitution of 0.5 mol% B i3+, showed the largest value of 325 μm at ±150 V square pulse. square pulse.are pulse..

  • PDF

Low Temperature Sintering of PNN-PZT Ceramics and Its Electrical Properties (PNN-PZT 세라믹스의 저온 소결 및 전기적 특성 평가)

  • Lee, Myung-Woo;Kim, Sung-Jin;Yoon, Man-Soon;Ryu, Sung-Lim;Kweon, Soon-Yong
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
    • /
    • v.21 no.12
    • /
    • pp.1077-1082
    • /
    • 2008
  • To fabricate a multi-layered piezoelectrics/electrodes structure, the piezoelectrics should be sintered at the temperature lower than 950C to use the silver electrode, which is cheaper than the electrodes containing noble metals such as Pd and Pt. Therefore, in this study, we modified the composition of Pb(Zr,Ti)O3-based material as (Pb0.98Cd0.02)(Ni1/3Nb2/3)0.25Zr0.35Ti0.4O3 to lower the sintering temperature and to improve the piezoelectric properties. Small amount of MnCO3, SiO2, and Pb3O4 were also added to lower the sintering temperature of the ceramic. The prepared raw powders were mixed by using a ball mill for 24 hours. And then the mixed powders were calcinated for 2 hours at 800C. The calcinated powders were again crushed with the ball mill for 72 hours. The final powders were pressed for making the shape of 15mm disk. The disk-type samples were sintered at temperature range of 850950C. The crystal phases of the sintered specimens were perovskite structure without secondary phases. All of the measured electrical properties such as electromechanical coupling coefficients (kp), mechanical quality factors (Qm), and piezoelectric charge constants (d33) were decreased with decreasing the sintering temperatures. The electrical properties measured at the sample sintered at 950C were 54% of kp, 503 of Qm, and 390 pC/N of d33, respectively. These properties were considered to be fairly good for the application of multi-layered piezoelectric generators or actuators.

Chemical Speciations of Elements in the Fe-Mn Crusts by Sequential Extraction (단계별 추출법을 이용한 망간각 구성 원소의 존재 형태)

  • Kim, Jong-Uk;Moon, Jai-Woon;Chi, Sang-Bum;Ko, Young-Tak;Lee, Hyun-Bok
    • Ocean and Polar Research
    • /
    • v.26 no.2
    • /
    • pp.231-243
    • /
    • 2004
  • Sequential extraction was carried out on twenty two subsamples of three ferromanganese crusts from three seamounts (Lemkein, Lomilik, and Litakpooki) near the Marshall Islands in the western Pacific. The extraction was designed to fractionate Fe-Mn crust forming elements into low defined groups: (1) exchangeable and carbornate, (2) Mn-oxide, (3) Fe-oxyhyd.oxide, and (4) residual fraction. X-ray diffraction result shows that target material were well removed by each extraction step except for CFA in phosphatized crusts generation. According to chemical analysis of each leachate, most of elements in the Fe-Mn crusts are bound with two major phases. Mn, Ba, Co, Ni, Zn, (Fe, Sr, Cu, and V) are strongly bounded with Mn-oxide (δMnO2) phase, whereas Fe, Ti, Zr, Mo, Pb, Al, Cu,(V, P, and Zn) show chemical affinity with Fe-oxyhydroxide phase. This result indicates that significant amount of Al, Ti, and Zr can not be explained by detrital origin. Ca, Mg, K, and Sr mainly occur as exchangeable elements and/or carbonate phase. Outermost layer 1 and inner layer 2 which are both young crusts generations are similar in chemical speciations of elements. However, some of Fe-oxyhydroxide bounded elements (Pb, Y, Mo, Ba, Al, and V) in phosphatized innermost layer 3 are released during phosphatization and incorporated into phosphate (Pb, Y, Mo, and Ba) or Mn-oxide phase (Al and V). Our sequential extraction results reveal that chemical speciations of elements in the hydrogenetic crusts are more or less different from interelemental relationship calculated by statistical method based on bulk chemistry.