• Title/Summary/Keyword: metallurgical technology

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The Metallization of Diamond Grits

  • Sung, James-C.;Hu, Shao-Chung;Chang, Yen-Shuo
    • Proceedings of the Korean Powder Metallurgy Institute Conference
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    • 2006.09b
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    • pp.1134-1135
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    • 2006
  • A revolutionary "Active Braze Coated Diamond" (ABCD) has been developed for bonding diamond grits firmly in the metal matrix. The molten braze is wetted and reacted with diamond to form strong chemical bond at the interface so that the diamond does not become knocked out of tools. The ABC is a nickel alloy that can form metallurgical diffusion bondswith the metal matrix. In essence, ABCD turns diamond into a metal grain so that the diamond tools can be made by conventional powder metallurgical process without being concerned about the poor bonding between matrix metal powder and the diamond as before.

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Basis for a Minimalistic Salt Treatment Approach for Pyroprocessing Commercial Nuclear Fuel

  • Simpson, Michael F.;Bagri, Prashant
    • Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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    • v.16 no.1
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    • pp.1-10
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    • 2018
  • A simplified flowsheet for pyroprocessing commercial spent fuel is proposed in which the only salt treatment step is actinide drawdown from electrorefiner salt. Actinide drawdown can be performed using a simple galvanic reduction process utilizing the reducing potential of gadolinium metal. Recent results of equilibrium reduction potentials for Gd, Ce, Nd, and La are summarized. A description of a recent experiment to demonstrate galvanic reduction with gadolinium is reviewed. Based on these experimental results and material balances of the flowsheet, this new variant of the pyroprocessing scheme is expected to meet the objectives of minimizing cost, maximizing processing rate, minimizing proliferation risk, and optimizing the utilization of geologic repository space.

Phase Transformation by the Oxidation of Air-passivated W and Mo Nanopowders Produced by an Electrical Explosion of Wires

  • Kwon, Young-Soon;Kim, Ji-Soon;A. Gromov, Alexander;Hong, Moon-Hee
    • Journal of Powder Materials
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    • v.11 no.2
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    • pp.130-136
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    • 2004
  • The passivation and oxidation process of tungsten and molybdenum narlopowders, produced by electrical explosion of wires was studied by means of FE-SEM, XPS. XRD, TEM, DIA-TGA and sire distribution analysis. In addition, the phase transformation of W and Mo nanopowders under oxidation in air was investigated. A chemical process is suggested for the oxidation of W and Mo nano-particles after a comprehensive testing of passivated and oxidized powders.

A Study on the 2-D Melt Fluid Flow Analysis by SMAC Method (SMAC법을 이용한 2차원 탕류해석에 관한 연구)

  • Choi, Jeong-Kil;Kim, Seoung-Bin;Hong, Chun-Pyo
    • Journal of Korea Foundry Society
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    • v.12 no.1
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    • pp.40-50
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    • 1992
  • A computer simulation of mold filling has been performed in order to analyze the fluid flow pattern in a mold cavity since casting defects such as cold shut formation, entrapment of air or gas, and inclusions are closely related to the fluid flow phenomena. The flow of molten metal entering the mold cavity with free surface has been modeled by SMAC(Simplified Marker and Cell) method. Two dimensional analysis was carried out on plate shape castings with two types of gate system. The calculation results were compared with those of water modeling experiments and showed relatively good agreement.

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Design of Fast Acting Fuse Characteristics Using a Precision Multi-layer Thin Film Plating (정밀 다층 박막 도금을 이용한 빠른 동작 퓨즈 특성 설계)

  • Kim, Eun-Min;Kang, Chang-Yong
    • The Transactions of The Korean Institute of Electrical Engineers
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    • v.65 no.3
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    • pp.445-451
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    • 2016
  • General fuse elements of solution for fast acting operation characteristics made using silver or silver alloy, those are not able to dominate cost competition to the advanced global leaders that have not only high technology but competitive price. In this study, the method that compose the fuse elements manufactured solution of fast acting operation characteristics by using precision multi-layer thin film plating and helical cutting process from low-priced copper metal. Furthermore, in order to move rated current line of fuse due to the heat loses, the manufacture construction method of fixed resistor is introduced, and then Ni-P plating layer and Sn plating layer are introduced multiply for controling fine opening time characteristics. So this study can establish the high productive and low-priced production method.

Evaluation of Iron Nickel Oxide Nanopowder as Corrosion Inhibitor: Effect of Metallic Cations on Carbon Steel in Aqueous NaCl

  • Chaudhry, A.U.;Mittal, Vikas;Mishra, Brajendra
    • Corrosion Science and Technology
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    • v.15 no.1
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    • pp.13-17
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    • 2016
  • The aim of this study was to evaluate the use of iron-nickel oxide ($Fe_2O_3$.NiO) nanopowder (FeNi) as an anti-corrosion pigment for a different application. The corrosion protection ability and the mechanism involved was determined using aqueous solution of FeNi prepared in a corrosive solution containing 3.5 wt.% NaCl. Anti-corrosion abilities of aqueous solution were determined using electrochemical impedance spectroscopy (EIS) on line pipe steel (API 5L X-80). The protection mechanism involved the adsorption of metallic cations on the steel surface forming a protective film. Analysis of EIS spectra revealed that corrosion inhibition occurred at low concentration, whereas higher concentration of aqueous solution produced induction behavior.

Development of Sugar Sensitive Drosophila Cell based ISFET Sensor for Alzheimer's Disease Diagnosis (알츠하이머 진단을 위한 당성분에 민감한 초파리 세포기반 ISFET센서개발)

  • Lim, Jeong-Ok;Yu, Joon-Boo;Kwon, Jae-Young;Byun, Hyung-Gi;Huh, Jeung-Soo;Cho, Won-Ju
    • Journal of Sensor Science and Technology
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    • v.22 no.4
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    • pp.281-285
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    • 2013
  • In this study a biosensor was developed by using Drosophila cells expressing a gustatory receptor Gr5a and an ion sensitive field effect transistors (ISFETs) sensor device, which demonstrated significant compatibility with the Drosophila cells expressing Gr5a and their response to sugar. These results suggested that the newly developed cell based biosensor has a potential as a simple and easy screening device for Alzheimer's disease in the future.

Tantalum Powder Preparation from Ta2O5 by Calciothermic Reduction (칼슘 열환원법에 의한 Ta2O5로부터 Ta분말제조)

  • Ha, Jung-Woo;Sohn, Ho-Sang;Jung, Jae-Young
    • Korean Journal of Metals and Materials
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    • v.50 no.11
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    • pp.823-828
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    • 2012
  • Direct reduction of $Ta_2O_5$ using liquid calcium was investigated. The experiment was conducted in a closed stainless steel chamber in an Ar atmosphere for 5-120 minutes. Most of $Ta_2O_5$ was reduced to ${\alpha}-Ta$ in 30 minutes above 1173 K and at a molar ratio of Ca and $Ta_2O_5$ above 10. The particles size increased with the reaction temperature, but it did not change much above 1223 K. The oxygen content of metal Ta was about 1 wt%.