• Title/Summary/Keyword: Ag Powder

Search Result 319, Processing Time 0.032 seconds

Brazing Adhesion Properties of Ag Coated W-Ag Electric Contact on the Cu Substrate (Ag 코팅한 W-Ag 전기접점/Cu 모재간의 브레이징 접합 특성)

  • Kang Hyun-Goo;Kang Yun-Sung;Lee Jai-Sung
    • Journal of Powder Materials
    • /
    • v.13 no.1 s.54
    • /
    • pp.18-24
    • /
    • 2006
  • The brazing adhesion properties of Ag coated W-Ag electric contact on the Cu substrate have been investigated in therms of microstructure, phase equilibrium and adhesion strength. Precoating of Ag layer ($3{\mu}m$ in thickness) on the $W-40\%Ag$ contact material was done by electro-plating method. Subsequently the brazing treatment was conducted by inserting BCuP-5 filler metal (Ag-Cu-P alloy) layer between Ag coated W-Ag and Cu substrate and annealing at $710^{\circ}C$ in $H_2$ atmosphere. The optimum brazing temperature of $710^{\circ}C$ was semi-empirically calculated on the basis of the Cu atomic diffusion profile in Ag layer of commercial electric contact produced by the same brazing process. As a mechanical test of the electric contact after brazing treatment the adhesion strength between the electric contact and Cu substrate was measured using Instron. The microstructure and phase equilibrium study revealed that the sound interlayer structure was formed by relatively low brazing treatment at $710^{\circ}C$. Thin Ag electro-plated layer precoated on the electric contact ($3{\mu}m$ in thickness) is thought to be enough for high adhesion strength arid sound microstructure in interface layer.

Fabrication and Characterization of Ag Nanoparticle Dispersed Polymer Nanofiber and Ag Nanofiber Using Electrospinning Method (전기방사법을 이용한 Ag 나노입자 분산 고분자 나노파이버와 Ag 나노파이버 제조 및 특성 평가)

  • Kim, Hee-Taik;Hwang, Chi-Yong;Song, Han-Bok;Lee, Kun-Jae;Joo, Yeon-Jun;Hong, Seong-Jei;Kang, Nam-Kee;Park, Seong-Dae;Kim, Ki-Do;Cho, Yong-Ho
    • Journal of Powder Materials
    • /
    • v.15 no.2
    • /
    • pp.114-118
    • /
    • 2008
  • Functional nanomaterial is expected to have improved capacities on various fields. Especially, metal nanoparticles dispersed in polymer matrix and metal nanofiber, one of the functional nanomaterials, are able to achieve improvement of property in the electric and other related fields. In this study, the fabrication of metal (Ag) nanoparticle dispersed nanofibers were attempted. The Ag nanoparticle dispersed polymer nanofiber and Ag nanofiber were fabricated by electrospinning method using electric force. First, PVP/$AgNO_3$ nanofibers were synthesized by electrospinning in $18{\sim}22kV$ voltage with the starting materials (Ag-nitrate) added polymer (PVP; poly (vinylpyrrolidone)). Then Ag nanoparticle dispersed polymer nanofibers were fabricated to reduce hydrogen reduction at $150^{\circ}C$ for 3hr. And Ag nanofibers were synthesized by the decomposited of PVP at $300{\sim}500^{\circ}C$ for 3hr. The nanofibers were analyzed by XRD, TGA, FE-SEM and TEM. The experimental results showed that the Ag nanofibers could be applied in many fields as an advanced material.

A Study on Multi-Filament Drawing of Bi2223 High-Temperature Superconductivity Wire by FE Method (유한요소법에 의한 Bi2223 고온 초전도 선재의 다심 인발에 대한 연구)

  • 박동인;김병민;오상수
    • Transactions of Materials Processing
    • /
    • v.13 no.1
    • /
    • pp.78-83
    • /
    • 2004
  • High-temperature superconduction materials(Bi2223) possess electrical/electronic and magnetic properties. Because high-temperature superconduction materials is a ceramic powder, that cannot be produced singlehandedly. So Ag sheathed Bi-2223 wire was produced by drawing process using powder-in-tube(PIT) method. This superconductor has many difficulties to produce. The main difficulty is that the mechanical properties of the ceramic powder are very different from those of the Ag sheath. And by these properties, Bi2223 high-temperature superconductor, which has a single filament drawing process and multi-filament drawing process, has a defect like sausaging and bursting at a center. This study analyzed multi-filament drawing process by FEM, and a defect generated during multi-filament drawing was studied by FEH. Specially, in order to prevent a bursting at a center, this study presented a method that inserts a pure Ag at a center of multi-filament wire

Surface Modification of Ag Coated Cu Conductive Metal Powder for Conductive Silicone Sealant Gasket Paste

  • Park, Seong-Yong;Yoon, Tae-Won;Lee, Chung-Ho;Jeong, In-Bum;Hyun, Sang-Hoon
    • Proceedings of the Korean Powder Metallurgy Institute Conference
    • /
    • 2006.09b
    • /
    • pp.1076-1077
    • /
    • 2006
  • Conductive pastes consist of conductive fillers( Au, Ag, Ni, Cu etc.), organic binders, solvents and additives. Meanwhile, there are some metal powders such as copper, nickel etc that are used for pastes which have serious surface corrosion problems. This problem leads to change of the color and decrease in conductivity and affect storage stability of conductive pastes. By using silane coupling agent and dispersion agent, we can ensure both the corrosion stability and long term storage stability, and enhance the high performance electrical and mechanical properties of EMI shielding silicone sealant.

  • PDF

Synethisis of fine BSCCO precursor powder by spray pyrolysis (분무 열분해에 의한 미세 BSCCO 전구체 분말의 합성)

  • 김성환;유재무;고재웅;김영국;박성창
    • Proceedings of the Korea Institute of Applied Superconductivity and Cryogenics Conference
    • /
    • 2003.10a
    • /
    • pp.99-102
    • /
    • 2003
  • Many researches on synthesis process for BSCCO precursor powders have been developed for high J$_{c}$ BSCCO-2223/Ag tape. Spray pyrolysis method for fabrication of precursor powder has many advantages, such as high purity, fine particle size of BSCCO precursor powder. Fine, spherical powders were prepared by ultrasonic spray pyrolysis from the aqueous solution of metal nitrates. BSCCO precursor powders were synthesized with 0.1 M concentration and heat treatment conditions. Average particle size for spray pyrolysis powders was 1.5 ~ 3 ${\mu}{\textrm}{m}$. BSCCO -2223/Ag tape was prepared by PIT method and followed by various sintering conditions. The critical current density of BSCCO-2223/Ag tape sintered in low oxygen partial pressure was ~ 23 kAcm$^{-2}$.

  • PDF

Fabrication and Characterization of Ag Particles by Polyol Process and Wet Chemical Process (폴리올 공정과 액상 환원 공정에 따른 은 입자 제조 및 특성 평가)

  • Yoo, Juyeon;Jang, Hyosung;Lee, Kun-Jae
    • Journal of Powder Materials
    • /
    • v.23 no.4
    • /
    • pp.297-302
    • /
    • 2016
  • Ag nanoparticles are extensively studied and utilized due to their excellent catalysis, antibiosis and optical properties. They can be easily synthesized by chemical reduction methods and it is possible to prepare particles of uniform size and high purity. These methods are divided into vapor methods and liquid phase reduction methods. In the present study, Ag particles are prepared and analyzed through two chemical reduction methods using solvents containing a silver nitrate precursor. When Ag ions are reduced using a reductant in the aqueous solution, it is possible to control the Ag particle size by controlling the formic acid ratio. In addition, in the Polyol process, Ag nanoparticles prepared at various temperatures and reaction time conditions have multiple twinned and anisotropic structures, and the particle size variation can be confirmed using field emissions scanning electron microscopy and by analyzing the UV-vis spectrum.

A Study on the Effects of Ag Addition on the Mechanical Properties and Microstructure in Atomized Al-Zn-Mg Alloys (분무 Al-Zn-Mg 합금의 기계적 성질 및 미세조직에 미치는 Ag 첨가의 영향)

  • Shin, Hee-Sang;Jeong, Tae-Ho;Nam, Tae-Woon
    • Journal of Korea Foundry Society
    • /
    • v.19 no.6
    • /
    • pp.456-465
    • /
    • 1999
  • The overall objective of this study is to investigate the effect of Ag addition on the mechanical properties and microstructure of rapid solidified 7000 Al series alloys. Al-Zn-Mg-Cu alloys with small amounts of Ag was fabricated into the powder by gas atomization. The powder was extruded after the cold compaction and degassing and then followed by T6 heat treatment. Microstructure observation, phase analysis, room and high temperature tensile test and hardness test were pursued. The tensile strength and hardness of Ag-added alloy after heat treatment was increased with increasing Ag contents. However, the elongation of extruded alloys was not increased as much as to be expected. The reason of this result seems to be related to $the{\Omega}$ phase, which contribute to the high temperature strength stability of Al-Cu-Zn alloys through the formation of eutectoid with Ag addition.

  • PDF

Effect of Post Heat Treatment on the Microstructure and Mechanical Properties of BCuP-5 Filler Metal Coating Layers Fabricated by High Velocity Oxygen Fuel Thermal Spray Process on Ag Substrate (고속 화염 용사 공정으로 제조된 BCuP-5 필러 금속 코팅층/Ag 기판 클래드 소재의 후열처리에 따른 미세조직 및 기계적 특성 변화)

  • Park, So-Yeon;Youn, Seong-June;Park, Jae-Sung;Lee, Kee-Ahn
    • Journal of Powder Materials
    • /
    • v.29 no.4
    • /
    • pp.283-290
    • /
    • 2022
  • A Cu-15Ag-5P filler metal (BCuP-5) is fabricated on a Ag substrate using a high-velocity oxygen fuel (HVOF) thermal spray process, followed by post-heat treatment (300℃ for 1 h and 400℃ for 1 h) of the HVOF coating layers to control its microstructure and mechanical properties. Additionally, the microstructure and mechanical properties are evaluated according to the post-heat treatment conditions. The porosity of the heat-treated coating layers are significantly reduced to less than half those of the as-sprayed coating layer, and the pore shape changes to a spherical shape. The constituent phases of the coating layers are Cu, Ag, and Cu-Ag-Cu3P eutectic, which is identical to the initial powder feedstock. A more uniform microstructure is obtained as the heat-treatment temperature increases. The hardness of the coating layer is 154.6 Hv (as-sprayed), 161.2 Hv (300℃ for 1 h), and 167.0 Hv (400℃ for 1 h), which increases with increasing heat-treatment temperature, and is 2.35 times higher than that of the conventional cast alloy. As a result of the pull-out test, loss or separation of the coating layer rarely occurs in the heat-treated coating layer.

Preparation and Antibacterial Properties of the Planar-Type ZnO Powder Coated with Ag or CuO (Ag 또는 CuO를 코팅한 평판형 ZnO 분말의 합성 및 항균성 평가)

  • Hong, Da-Hee;Gwack, Ji-Yoo;Jeon, Deock-Seong;Jo, Dong-Hyeon;Lee, Gun-Sub;Lee, Jung-Hwan;Lee, Hee-Chul
    • Journal of the Korean institute of surface engineering
    • /
    • v.54 no.3
    • /
    • pp.144-151
    • /
    • 2021
  • In the present work, planar-type ZnO powder of [0001] plane with a high aspect ratio range of 20:1 to 50:1 was synthesized. Ag or CuO could be coated on the planar-type ZnO powder by wet methods such as centrifugation or ball milling. During the coating, the average size of the powder was slightly increased while maintaining the shape and XRD pattern of ZnO. When Ag or CuO was coated, the absolute value of the zeta potential, as well as the concentration of oxygen vacancy, was increased. Ag or CuO coated planar-type ZnO power exhibited excellent antibacterial performance, which seems to be related to their high electrostatic attraction force. They could be made into a masterbatch by mixing with ABS resin, and their applicability to antibacterial substances was confirmed by manufacturing the caps of a keyboard.