• 제목/요약/키워드: Ni alloy

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치과용 Ni-Ti합금의 표면특성에 미치는 Mo함량의 영향 (Effects of Mo Content on Surface Characteristics of Dental Ni-Ti Alloys)

  • 최한철;김재운;박순균
    • Corrosion Science and Technology
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    • 제22권1호
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    • pp.64-72
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    • 2023
  • Ni-Ti shape memory alloy for dental nerve treatment devices was prepared by adding Mo to Ni-Ti alloy to improve flexibility and fatigue fracture characteristics and simultaneously increase corrosion resistance. Surface properties of the alloy were evaluated. Microstructure analysis of the Ni-Ti-xMo alloy revealed that the amount of needle-like structure increased with increasing Mo content. The shape of the precipitate showed a pattern in which a long needle-like structure gradually disappeared and changed into a small spherical shape. As a result of XRD analysis of the Ni-Ti-xMo alloy, R-phase structure appeared as Mo was added. R-phase and B2 structure were mainly observed. As a result of DSC analysis, phase transformation of the Ti-Ni-Mo alloy showed a two-step phase change of B2-R-B19' transformation with two exothermic peaks and one endothermic peak. As Mo content increased, R-phase formation temperature gradually decreased. As a result of measuring surface hardness of the Ti-Ni-Mo alloy, change in hardness value due to the phase change tended to decrease with increasing Mo content. As a result of the corrosion test, the corrosion potential and pitting potential increased while the current density tended to decrease with increasing Mo content.

아말감과 이종(異種)금속의 거리에 따른 부식에 대한 고찰 (A Study on Corrosion according to Distance between Amalgam and Dissimilar Metals)

  • 김주원;정은경
    • 치위생과학회지
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    • 제4권3호
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    • pp.103-109
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    • 2004
  • 본 실험은 제조회사 매뉴얼과 통법에 의해서 Amalgam 합금, Ni-Cr alloy의 Crown용 Verabond, Denture용 Talladium $^{TM}alloy$로 각각 24개의 총 72의 시편을 하악 제1대구치근 원심 치관 폭경과 임상에서의 MOD cavity를 고려하여 제작하였고 인공 타액 80ml를 담은 200ml 용 비이커에 시편을 넣어 0mm, 7mm, 40mm 거리에서 7일 후 갈바닉 부식을 측정하였다. 유리금속은 유도 플라즈마 방출 분광기(Inductively Coupled Plasma - Atomic Emission Spectrometer(ICP-AES, JY-50P, VG Elemental Co. France)로 전해액내의 Cu, Ag, Ni, Cr, Sn, Zn, Hg를 정량 분석했으며 그 결과 다음과 같은 결론을 얻었다. 첫째, Cu, Sn, Ag, Hg, Zn은 아말감이 금 합금과 접촉했을 때가 크라운용 Ni-Cr alloy와 덴쳐용 Talladium alloy 보다 아주 많이 유리 했으며 금 합금이 구강조직과 생체 적합성이 가장 좋다지만 아말감과 함께 있을 때 가장 불리 했슴을 알 수 있었다. 둘째, 아말감이 금 합금과 접촉했을 때, 금 합금의 조성에서 Ni, Cr 같은 중금속이 함유되지 않았기 때문인지 전혀 유리되지 않았으나 Sn은 조성에는 없었지만 $227.1{\pm}18.0035{\mu}g/cm^2$나 유리 되었고 Hg도 유리되었는데 이는 아말감 자체의 유리 물질임을 추측할 수 있었다. 셋째, 아말감 합금과 금 합금 사이에서의 0mm, 7mm, 40mm 거리에서는 Cu, Ag는 유의성이 있었으며 Hg는 유의성이 없었다. 이는 금합금은 절대 아말감과 같이 사용해서 안되며 이종 보철물 사이의 거리에 관계없이 사용을 금해야 하는 것으로 사료된다. 넷째, 아말감합금이 Crown용 Ni-Cr 합금과 접촉했을 때 아말감의 Ag이 유리 되지 않았으며 Zn, Ni, Sn, Hg, Cu의 순으로 유리되었다. 0mm, 7mm, 40mm 거리에 따라서 유의성이 있었다. Hg는 유리 되지 않았지만 중금속인 Ni, Cr은 유리되었고 반대 악궁이나 거리가 떨어져 있으면 접촉보다 Hg의 유리가 적었다. 다섯째, 아말감합금이 Denture용 Talladium alloy 합금과 접촉했을 때 0mm, 7mm, 40mm 거리에서도 유의성이 있었다. 0mm, 7mm, 40mm 거리에 따라서 유의성이 있었다. Hg는 유리 되지 않았지만 중금속인 Ni, Cr은 유리되었고 반대 악궁이나 거리가 떨어져 있으면 접촉보다 Hg의 유리가 적었다. 여섯째, 인공 타액에서 접촉 시 Amalgam alloy와 Gold, Verabond, Talladium alloy의 Cu, Sn, Ag, Hg, Zn, Ni, Cr의 ICPES 검사 결과 Cu, Hg가 유의성을 있었다. 일곱째, 인공타액에서 아말감합금과 두 비귀금속인 Ni-Cr alloy(crown용), Denture용 Talladium alloy가 접촉한 경우 거리에 따른 Hg, Ni, Cr의 유리 부산물에서 유의성을 확인했다.

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증용량 송전선 강심용 저열팽창 Fe-Ni-Co 합금에 있어서 용체화처리 영향 (Effect of Heat-treatment in Low Thermal Expansion Coefficient Fe-Ni-Co alloy for Core Material of Increased Capacity Transmission Line)

  • 김봉서;유경재;김병걸;이희웅
    • 한국전기전자재료학회:학술대회논문집
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    • 한국전기전자재료학회 2000년도 하계학술대회 논문집
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    • pp.950-952
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    • 2000
  • Considering the effective distribution coefficient of Ni in Fe-Ni-Co invar alloy containing a little amount of carbon, we investigated on the thermal expansion coefficient(${\alpha}$). Fe-Ni-Co invar alloy had a large thermal expansion coefficient in as-casted compared with solution treated. The thermal expansion coefficient of Fe-Ni-Co alloy increased with the carbon content in both state of as-casted and solution treated. The effective distribution coefficient(Ke$\^$Ni/) of Ni was smaller than unity in alloy of not containing carbon, but is way larger than unity in alloy of containing carbon. It was considered that the homogeneity of Ni in primary austenite affected thermal expansion coefficient.

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산소 농도 제어를 통한 NiCrAl 합금 폼 표면의 침상 NiO 보호층 효과 (Effect of Needle-Like NiO Protecting Layer on NiCrAl Alloy Foam by Controlled Oxygen Concentration)

  • 이영근;신동요;안효진
    • 한국재료학회지
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    • 제28권6호
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    • pp.324-329
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    • 2018
  • Needle-like NiO protecting layers on NiCrAl alloy foam, used as support for hydrogen production, are introduced through electroplated Ni and subsequent microwave annealing. To improve the stability of the NiCrAl alloy foam, oxygen concentration of microwave annealing to form a needle-like NiO layer with good chemical stability and corrosion resistance is controlled in a range of 20 and 50 %. As the oxygen concentration increases to 50 %, needle-like NiO forms a dense coating layer on the NiCrAl alloy foam; this layer formation can be attributed to accelerated growth of the (200) plane. In addition, the increased oxygen concentration causes increased NiO/Ni ratio of the resultant coating layer on NiCrAl alloy foam due to improved rate of the oxidation reaction. As a result, the introduction of dense needle-like NiO layers formed at 50 % oxygen concentration improves the chemical stability of the NiCrAl alloy foam by protecting the direct electrochemical reaction between the electrolyte and the foam. Thus, needle-like NiO can be proposed as a superb protecting layer to improve the chemical stability of NiCrAl alloy form.

MgNi계 수소흡장합금의 충방전특성 (Charge-discharge Characteristic of the Mg-Ni Hydrogen Storage Alloy System)

  • 오명학;정원섭;김인곤
    • 한국수소및신에너지학회논문집
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    • 제10권3호
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    • pp.177-184
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    • 1999
  • The charge-discharge characteristics of the $Mg_2Ni-x$ wt.%Nd (x = 0~3) electrodes were investigated. The electrodes were prepared by the mechanical grinding of the induction-melted $Mg_2Ni$ alloy powders with Ni and/or Nd using planetary ball mill apparatus. The discharge capacity of the $Mg_2Ni$ alloy increased with the increase in the nickel content. The electrode possessing 100 wt.% nickel powder showed the initial capacity of 760 mAh/g and the capacity decay with the cycle number was less than that of the 55 wt.% nickel powder. The Nd was added to this composition. It was found that the $Mg_2Ni-100$ wt.%Ni -0.2 wt.%Nd alloy showed an excellent charge-discharge cycle characteristics compared with the other reported Mg-Ni alloy system. The discharge capacity was 400 mAh/g after 70 cycles. Such an improved cycle life seems to be attributed to the improvement in the corrosion characteristics of the alloy. The anodic polarization curve of the $Mg_2Ni-100$ wt.%Ni-0.2 wt.%Nd alloy exhibited better passivating behavior than that of the $Mg_2Ni-100$ wt.%Ni.

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Fe-Co-Ni합금박막의 조성 및 자기적 성질 (Composition and Coercivity of Fe-Co-Ni Alloy Electrodeposits)

  • 예길촌;김용웅;문근호
    • 한국표면공학회지
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    • 제29권3호
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    • pp.195-202
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    • 1996
  • The composition, the microstructure and the magnetic properties(HC and Hk) of Fe-Co-Ni alloy electrodeposits were investigated according to the electrolysis conditions using sulfate bath paddle agitated. The current efficiency of the alloys electrodeposition was considerably low in the range of 16∼50%. The Fe content(wt.%) of the alloy increased from 20% to 57% with current density, while Ni content of them decreased in the range of 70∼24% respectively, and Co content was nearly constant. As a result, Fe/Ni ratio of the alloy increased from 0.3 to 2.0 showing the anomalous codeposition. The structure of the alloy changed from fcc to the mixed one of fcc+bcc with the increase of Fe/Ni ratio. The preferred orientation of the alloy with fcc and bcc structure were (220) and (110) respectively. The alloy with Fe/Ni ratio(0.3∼l.2) had the lowest coercivity of 0.4∼0.8 Oe.

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NiW 기능성 합금도금을 위한 전해 (Electrolysis for NiW Functional Alloy Plating)

  • 정구진;이철경
    • 한국표면공학회지
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    • 제44권1호
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    • pp.1-6
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    • 2011
  • A NiW functional alloy plating was investigated as variables of metal ion concentration, complexing agent, temperature, pH and applied current density. Even if numerous studies on reaction mechanism of NiW induced codeposition were carried out during couples of decade, it has not been acceptable reaction mechanism. This study was focused on the effect of the plating variables on the alloy composition in the NiW alloy plating. Applied current density could control mainly the alloy composition rather than other plating variables. It has also been confirmed that the functional alloy plating such as layered or gradient plating was possible by controlling applied current density.

Ge-MOSFETs을 위한 Ni-Co 합금을 이용한 Ni-germanide의 열안정성 개선 (Thermal Stability Improvement of Ni-germanide using Ni-Co alloy for Ge-MOSFETs Technology)

  • 박기영;정순연;장잉이;한인식;이세광;종준;신홍식;김영철;김재준;이가원;왕진석;이희덕
    • 한국전기전자재료학회논문지
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    • 제21권8호
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    • pp.733-737
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    • 2008
  • In this paper, Ni-Co alloy was used to improve thermal stability of Ni Germanide. It was found that uniform germanide is obtained on epitaxial Ge-on-Si substrate by employing Ni-Co alloy. Moreover, neither agglomeration nor penetration is observed during post-germanidation annealing process. The thermal stability of Ni germanide using Ni-Co alloy is improved due to the less agglomeration of Germanide. Therefore, the proposed Ni-Co alloy is promising for highly thermal immune Ni germanide for nano scale Ge-MOSFETs technology.

Synthesis and electromagnetic properties of FeNi alloy nanofibers using an electrospinning method

  • Lee, Young-In;Choa, Yong-Ho
    • 한국결정성장학회지
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    • 제22권5호
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    • pp.218-222
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    • 2012
  • FeNi alloy nanofibers have been prepared by an electrospinning process followed by air-calcination and H2 reduction to develop electromagnetic (EM) wave absorbers in the giga-hertz (GHz) frequency range. The thermal behavior and phase and morphology evolution in the synthetic processes were systematically investigated. Through the heat treatments of calcination and H2 reduction, as-spun PVP/FeNi precursor nanofiber has been stepwise transformed into nickel iron oxide and FeNi phases but the fibrous shape was maintained perfectly. The FeNi alloy nanofiber had the high aspect ratio and the average diameter of approximately 190 nm and primarily composed of FeNi nanocrystals with an average diameter of ~60 nm. The FeNi alloy nanofibers could be used for excellent EM wave absorbing materials in the GHz frequency range because the power loss of the FeNi nanofibers increased up to 20 GHz without a degradation and exhibited the superior EM wave absorption properties compared to commercial FeNi nanoparticles.

원자로 압력용기용 Mn-Mo-Ni계 및 Ni-Mo-Cr계 저합금강의 미세조직과 기계적 특성 비교 (Comparison of Microstructure & Mechanical Properties between Mn-Mo-Ni and Ni-Mo-Cr Low Alloy Steels for Reactor Pressure Vessels)

  • 김민철;박상규;이봉상
    • 대한금속재료학회지
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    • 제48권3호
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    • pp.194-202
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    • 2010
  • Application of a stronger and more durable material for reactor pressure vessels (RPVs) might be an effective way to insure the integrity and increase the efficiency of nuclear power plants. A series of research projects to apply the SA508 Gr.4 steel in ASME code to RPVs are in progress because of its excellent strength and durability compared to commercial RPV steel (SA508 Gr.3 steel). In this study, the microstructural characteristics and mechanical properties of SA508 Gr.3 Mn-Mo-Ni low alloy steel and SA508 Gr.4N Ni-Mo-Cr low alloy steel were investigated. The differences in the stable phases between these two low alloy steels were evaluated by means of a thermodynamic calculation using ThermoCalc. They were then compared to microstructural features and correlated with mechanical properties. Mn-Mo-Ni low alloy steel shows the upper bainite structure that has coarse cementite in the lath boundaries. However, Ni-Mo-Cr low alloy steel shows the mixture of lower bainite and tempered martensite structure that homogeneously precipitates the small carbides such as $M_{23}C_6$ and $M_7C_3$ due to an increase of hardenability and Cr addition. In the mechanical properties, Ni-Mo-Cr low alloy steel has higher strength and toughness than Mn-Mo-Ni low alloy steel. Ni and Cr additions increase the strength by solid solution hardening. In addition, microstructural changes from upper bainite to tempered martensite improve the strength of the low alloy steel by grain refining effect, and the changes in the precipitation behavior by Cr addition improve the ductile-brittle transition behavior along with a toughening effect of Ni addition.