• Title/Summary/Keyword: Ag powder

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Preparation of Ag Powder from AgNO3 by Wet Chemical Reduction Method1. The Establishment of Optimum Reaction System for the Preparation of Spherical Ag Powder (습식 화학적 환원법에 의한 AgNO3로부터 Ag 분말의 제조 1. 균일한 구형 Ag 분말의 제조를 위한 최적 반응계 확립)

  • Yuna, Ki-Seok;Park, Young-Chul;Yang, Beom-Seok;MIn, Hyun-Hong;Won, Chang-Whan
    • Journal of Powder Materials
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    • v.12 no.1
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    • pp.56-63
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    • 2005
  • Ag powder was prepared from $AgNO_3$ by wet chemical reduction method using various reduction agent system involving $AgNO_3$, $AgNO_2$(AgCl) and Ag complex ion aqueous solution. The pure Ag powder could be prepared regardless of reaction system but the particle shape and distribution were affected very much according to the kind of reduction agents and reaction systems. The optimum reaction system for the preparation of the silver powder having the uniform particle shape and size distribution was Ag complex ion aqueous solution-reduction agent system and in particular, $H_2O_2$ and $C_6H_8O_6$as a reduction agent leaded the more uniform particle shape and size distribution.

Synthesis of Flake Ag Powder by Polyol Process (폴리올법에 의한 편상의 은 분말 합성)

  • Kim Dong-Jin;Liang Huanzhen;Ahn Jong-Gwan;Lee Jae-Ryeong;Chung Hun-Saeng
    • Journal of Powder Materials
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    • v.11 no.6 s.47
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    • pp.477-485
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    • 2004
  • Monodispersed flaky silver powder was obtained by controlling the ratios of $H_{2}O_{2}/NH_{3}$ and Agin in a mixed solution of ethylene glycol and ammonia with an addition of PVP. The effects of $NH_{3}/Ag,\; H_{2}O_{2}/Ag\;and\;H_{2}PtCl_{6}/Ag$ on its morphology and size were investigated. In $H_{2}O_{2}-NH_{3}-AgNO_{3}\;system,\;NH_{3}/Ag$ molar ratio was found to be an important reaction factor for the nucleation and crystal growth of Ag powder. The synthesis of flaky powder was optimized at over 6 of $NH_{3}/Ag \;and\;5\;of\;H_{2}O_{2}/Ag\;under\;1.0{\times}10^{-3}\;of\;Pt/Ag.\;Moreover,\;as\;the\; NH_{3}/Ag$ molar ratio increased, the size of precipitates was increased regardless of the amount of Pt. In the absence of $H_{2}PtCI$, the morphology and size of reduced Ag powder were found to be irregular in shape $2-4{\mu}m$ in diameter. However, homogenized fine Ag powder was obtained due to heterogeneous nucleation when $H_{2}PtCI$ used as a cat-alyst, and flaky one was synthesized with the addition of Pt over $1.0{\times}10^{-3}$ of Pt/Ag.

Preparation of Ag Powder by Wet Reduction Method using NaBH4 Reducing Agent (습식환원법에서 NaBH4환원제를 이용한 Ag분말의 제조)

  • Won Chang-Whan;Lee Huk-Hee
    • Journal of Powder Materials
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    • v.13 no.4 s.57
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    • pp.278-284
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    • 2006
  • Spherical Ag powder was prepared in the system of $AgNO_3\;and\;NaBH_4$ by wet chemical reduction method. The size of Ag powder was increased as the reaction temperature and the concentration of reducing agent was decreased in the constant concentration of dispersion agent. Optimum conditions of producing Ag powder having $1.39{\mu}m$ of D50 was 1M of $AgNO_3$, 0.5M of $NaBH_4$, 1.5g of Gelatine in the room temperature.

Production of Ag- Ni fine powder by coprecipitation (공침법을 이용한 Ag-Ni 초미분 제조)

  • Kim, Bong-Seo;Woo, Byung-Chul;Byun, Woo-Bong;Lee, Hee-Woong
    • Proceedings of the KIEE Conference
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    • 1994.07b
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    • pp.1342-1344
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    • 1994
  • Silver-Nickel alloy has been used as a electrical contact material for low voltage, low current. Since the solubility between Ag and Ni is very low, it is difficult to produce Ag-Ni alloy by using conventional melting method and disperse Ni powder homogeneously in Ag matrix. In this study we have been produced fine Ag-Ni alloy powder by using coprecipitation method. Firstly, we have produced silver-nickel nitrate solution by dissolving the Ag and Ni ingot in nitric acid solution and then, coprecipitate (Ag, Ni)carbonate dropping Ag-Ni nitrate solution to sodium carbonate solution. (Ag, Ni) carbonate is heat-treated in $H_2$ atmosphere, $400^{\circ}C$ and it has been analysed by TGA, SEM, XRD, ICP. It is represented Silver-Nickel alloy powder in the particle range of $0.1{\sim}0.5{\mu}m$.

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The Influence of Production Process Parameters on Properties W-Ag, Mo-Ag Composites

  • Lezanski, Jan;Madej, Marcin
    • Proceedings of the Korean Powder Metallurgy Institute Conference
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    • 2006.09b
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    • pp.1200-1201
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    • 2006
  • Attempts have been made to describe the influence of production process parameters on the microstructure and properties of W-Ag and Mo-Ag composites. The compositions of powder mixtures are W+30% Ag and Mo+30%Ag. Silver additions assists densification during sintering by a liquid phase sintering process. The main goal of this work is to compare properties and microstructure of as-sintered and as-infiltrated composites.

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Sintering Behavior of Ag-Ni Electrode Powder with Core-shell Structure

  • Kim, Kyung Ho;Koo, Jun-Mo;Ryu, Sung-Soo;Yoon, Sang Hun;Han, Yoon Soo
    • Journal of the Korean institute of surface engineering
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    • v.49 no.6
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    • pp.507-512
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    • 2016
  • Expensive silver powder is used to form electrodes in most IT equipment, and recently, many attempts have been made to lower manufacturing costs by developing powders with Ag-Ni or Ag-Cu core-shell structures. This study examined the sintering behavior of Ag-Ni electrode powder with a core-shell structure for silicon solar cell with high energy efficiency. The electrode powder was found to have a surface similar to pure Ag powder, and cross-sectional analysis revealed that Ag was uniformly coated on Ni powder. Each electrode was formed by sintering in the range of $500^{\circ}C$ to $800^{\circ}C$, and the specimen sintered at $600^{\circ}C$ had the lowest sheet resistance of $5.5m{\Omega}/{\Box}$, which is about two times greater than that of pure Ag. The microstructures of electrodes formed at varying sintering temperatures were examined to determine why sheet resistance showed a minimum value at $600^{\circ}C$. The electrode formed at $600^{\circ}C$ had the best Ag connectivity, and thus provided a better path for the flow of electrons.

Process Optimization of Environment-Friendly Ag-SnO2 Electric Contact Materials through a Powder Metallurgy (친환경 Ag-SnO2 전기접점재료의 분말야금 공정 최적화)

  • Kim, Jeong-Gon
    • Journal of Powder Materials
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    • v.14 no.5
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    • pp.327-332
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    • 2007
  • In a view point of environment, the advanced electric contact material without environmental load element such as cadmium has to be developed. Extensive studies have been carried out on $Ag-SnO_2$ electric contact material as a substitute of Ag-CdO contact materials. In the present study, powder metallurgy including compaction and sintering is introduced to solve the incomplete oxidation problems in manufacturing process of $Ag-SnO_2$ electrical contact material. The $Ag-SnO_2$ contact material, fabricated in this study, was actually set in an electric switchgear of which working voltage is 462V and current is between 25 and 40A, for the purpose of testing its performance. As a result, it exceeded the existing Ag-CdO contact materials in terminal-temperature ascent and main contact resistance.

A FACILE METHOD FOR THE PRODUCTION OF Sn-Ag ALLOY BY HIGH ENERGY BALL MILLING

  • ASHUTOSH SHARMA;BYUNGMIN AHN
    • Archives of Metallurgy and Materials
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    • v.65 no.4
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    • pp.1329-1333
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    • 2020
  • In this study, we have developed Sn-Ag alloy by a simple high energy ball milling technique. We have ball-milled the eutectic mixture of Sn and Ag powders for a period of 45 h. The milled powder for 45 h was characterized for particle size and morphology. Microstructural investigations were carried out by scanning electron microscopy and X-ray diffraction studies. The melting behavior of 45 h milled powder was studied by differential scanning calorimetry. The resultant crystallite size of the Sn(Ag) solid solution was found to be 85 nm. The melting point of the powder was 213.6℃ after 45 h of milling showing depression of ≈6℃ in melting point as compared to the existing Sn-3.5Ag alloys. It was also reported that the wettability of the Sn-3.5Ag powder was significantly improved with an increase in milling time up to 45 h due to the nanocrystalline structure of the milled powder.

Development of the Copper Core Balls Electroplated with the Solder of Sn-Ag-Cu

  • Imae, Shinya;Sugitani, Yuji;Nishida, Motonori;kajita, Osamu;Takeuchi, Takao
    • Proceedings of the Korean Powder Metallurgy Institute Conference
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    • 2006.09b
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    • pp.1207-1208
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    • 2006
  • We developed the copper core ball electroplated with Sn-Ag-Cu of the eutectic composition which used mostly as Pb free solder ball with high reliability. In order to search for the practicality of this developed copper core ball, the evaluation was executed by measuring the initial joint strength of the sample mounted on the substrate and reflowed and by measuring the joint strength of the sample after the high temperature leaving test and the constant temperature and the humidity leaving test. This evaluation was compered with those of the usual other copper core balls electroplated with (Sn,Sn-Ag,Sn-Cu,Sn-Bi) and the Sn-Ag-Cu solder ball.

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