• Title/Summary/Keyword: Eutectic temperature

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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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A study on the MC Carbide Morphologies Directionally Solidified Superalloys (일방향응고 초내열합금에서 MC 탄화물 형상에 관한 연구)

  • Kim, Seung-Eon;Jo, Chang-Yong;Kim, Hak-Min
    • 한국기계연구소 소보
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    • s.20
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    • pp.57-63
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    • 1990
  • The morphologies of MC carbides (M stands for metal) and creep-rupture properties in directionally solidified Rene 80 having standard and Hf-modified chemistries were studied. It was found that Hf depressed the melting point, $\gamma$- $\gamma$’ eutectic temperature and $\gamma$’ solvus of nickel-base superalloy Rene 80, but did not depress MC carbide forming temperature. The morphologies of MC carbides depended upon solidification sequence, which led to blocky type in the early stage and script type in the late stage of solidification. Creep failure occurs through the crack initiation at the transverse components of longitudinal grain boundaries or interdendritic carbides in directionally solidified superalloys. It could be concluded MC carbide morphologies played an important role in creep properties of DS superalloys, that is, Hf additions increased the creep ductilities and lives of Rene 80.

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Semi-Solid Forming of Al-Zn-Mg-Cu Alloy Applying Low-Temperature Casting Process (저온 주조법을 응용한 Al-Zn-Mg-Cu 합금의 반응고 성형)

  • Kim, Jeong-Min;Kim, Ki-Tae;Jung, Woon-Jae
    • Journal of Korea Foundry Society
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    • v.22 no.2
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    • pp.82-88
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    • 2002
  • Al-5.5Zn-2.5Mg-l.5Cu semi-solid slurry was prepared by cooling the liquid metal with a low superheat to a solid and liquid co-existing temperature. Relatively round solid particles could be obtained in the slurry through the simple process. The prepared slurry was deformed into the metallic mold by a press and the mechanical properties of obtained specimens were investigated. Mold filling ability of the alloy slurry was also investigated and compared with that of A356 alloy. Al-Zn-Mg-Cu alloy showed lower mold filling ability than A356 alloy probably because small amount of eutectic phase is present and the heat of fusion generated during solidification is smaller than that of A356 alloy.

The Wetting Property of Sn-3.5Ag Eutectic Solder (Sn-3.5Ag 공정 솔더의 젖음특성)

  • 윤정원;이창배;서창제;정승부
    • Journal of Welding and Joining
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    • v.20 no.1
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    • pp.91-96
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    • 2002
  • Three different kinds of substrate used in this study : bare Cu, electroless Ni/Cu substrate with a Nilayer thickness of $5\mu\textrm{m}$, immersion Au/electroless Ni/Cu substrate with the Au and Ni layer of $0.15\mu\textrm{m}$ and $5\mu\textrm{m}$ thickness, respectively. The wettability and interfacial tension between various substrate and Sn-3.5Ag solder were examined as a function of soldering temperature, types of flux. The wettability of Sn-3.5Ag solder increased with soldering temperature and solid content of flux. The wettability of Sn-3.5Ag solder was affected by the substrate metal finish used, i.e., nickel, gold and copper. Intermetallic compound formation between liquid solder and substrate reduced the interfacial energy and decreased wettability.

Electrochemical extraction of uranium on the gallium and cadmium reactive electrodes in molten salt

  • Valeri Smolenski;Alena Novoselova
    • Nuclear Engineering and Technology
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    • v.56 no.1
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    • pp.42-47
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    • 2024
  • The electrochemical extraction of uranium in ternary low melting LiCl-KCl-CsCl eutectic on inert and reactive electrodes via different electrochemical techniques was investigated. It was established that the electrochemical reduction process of U(III) ions on the inert W electrode was irreversible and proceeded in one stage. On reactive liquid Ga and liquid Cd electrodes the reduction of uranium ions took place with the considerable depolarization with the formation of UGa2, UGa3 and UCd11 intermetallic compounds. Thermodynamic characteristics of uranium compounds and alloys were calculated. The conditions for the extraction of uranium from the electrolyte in the form of alloys on both liquid reactive electrodes via potentiostatic electrolysis were found.

Temperature Calibration of a Specimen-heating Holder for Transmission Electron Microscopy

  • Kim, Tae-Hoon;Bae, Jee-Hwan;Lee, Jae-Wook;Shin, Keesam;Lee, Joon-Hwan;Kim, Mi-Yang;Yang, Cheol-Woong
    • Applied Microscopy
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    • v.45 no.2
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    • pp.95-100
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    • 2015
  • The in-situ heating transmission electron microscopy experiment allows us to observe the time- and temperature-dependent dynamic processes in nanoscale materials by examining the same specimen. The temperature, which is a major experimental parameter, must be measured accurately during in-situ heating experiments. Therefore, calibrating the thermocouple readout of the heating holder prior to the experiment is essential. The calibration can be performed using reference materials whose phase-transformation (melting, oxidation, reduction, etc.) temperatures are well-established. In this study, the calibration experiment was performed with four reference materials, i.e., pure Sn, Al-95 wt%Zn eutectic alloy, NiO/carbon nanotube composite, and pure Al, and the calibration curve and formula were obtained. The thermocouple readout of the holder used in this study provided a reliable temperature value with a relative error of <4%.

Non-linear Temperature Dependent Deformation Anaysis of CBGA Package Assembly Using Moir′e Interferometry (모아레 간섭계를 이용한 CBGA 패키지의 비선형 열변형 해석)

  • 주진원;한봉태
    • Journal of the Microelectronics and Packaging Society
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    • v.10 no.4
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    • pp.1-8
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    • 2003
  • Thermo-mechanical behavior of a ceramic ball grid array (CBGA) package assembly are characterized by high sensitive moire interferometry. Moir fringe patterns are recorded and analyzed at various temperatures in a temperature cycle. Thermal-history dependent analyses of global and local deformations are presented, and bending deformation (warpage) of the package and shear strain in the rightmost solder ball are discussed. A significant non-linear global behavior is documented due to stress relaxation at high temperature. Analysis of the solder interconnections reveals that inelastic deformation accumulates on only eutectic solder fillet region at high temperatures.

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Uncooled Microbolometer FPA Sensor with Wafer-Level Vacuum Packaging (웨이퍼 레벨 진공 패키징 비냉각형 마이크로볼로미터 열화상 센서 개발)

  • Ahn, Misook;Han, Yong-Hee
    • Journal of Sensor Science and Technology
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    • v.27 no.5
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    • pp.300-305
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    • 2018
  • The uncooled microbolometer thermal sensor for low cost and mass volume was designed to target the new infrared market that includes smart device, automotive, energy management, and so on. The microbolometer sensor features 80x60 pixels low-resolution format and enables the use of wafer-level vacuum packaging (WLVP) technology. Read-out IC (ROIC) implements infrared signal detection and offset correction for fixed pattern noise (FPN) using an internal digital to analog convertor (DAC) value control function. A reliable WLVP thermal sensor was obtained with the design of lid wafer, the formation of Au80%wtSn20% eutectic solder, outgassing control and wafer to wafer bonding condition. The measurement of thermal conductance enables us to inspect the internal atmosphere condition of WLVP microbolometer sensor. The difference between the measurement value and design one is $3.6{\times}10-9$ [W/K] which indicates that thermal loss is mainly on account of floating legs. The mean time to failure (MTTF) of a WLVP thermal sensor is estimated to be about 10.2 years with a confidence level of 95 %. Reliability tests such as high temperature/low temperature, bump, vibration, etc. were also conducted. Devices were found to work properly after accelerated stress tests. A thermal camera with visible camera was developed. The thermal camera is available for non-contact temperature measurement providing an image that merged the thermal image and the visible image.

The Effect of Extrusion Temperatures on Microstructures and Mechanical Properties of Ultra-Fine Structured and Extruded Al81Si19 Alloys (초 미세조직 Al81Si19 합금분말 압출재의 미세조직과 기계적 성질에 미치는 압출온도의 영향)

  • 이태행;홍순직
    • Journal of Powder Materials
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    • v.10 no.5
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    • pp.325-332
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    • 2003
  • The effect of extrusion temperature on the microstructure and mechanical properties was studied in gas atomized TEX>$Al_{81}Si_{19}$ alloy powders and their extruded bars using SEM, tensile testing and wear testing. The Si particle size of He-gas atomized powder was about 200-800 nm. Each microstructure of the extruded bars with extrusion temperature (400, 450 and 50$0^{\circ}C$) showed a homogeneous distribution of primary Si and eutectic Si particles embedded in the Al matrix and the particle size varied from 0.1 to 5.5 ${\mu}m$. With increasing extrusion temperature from 40$0^{\circ}C$ to 50$0^{\circ}C$, the ultimate tensile strength (UTS) decreased from 282 to 236 ㎫ at 300 K and the specific wear increased at all sliding speeds due to the coarse microstructure. The fracture behavior of failure in tension testing and wear testing was also studied. The UTS of extrudate at 40$0^{\circ}C$ higher than that of 50$0^{\circ}C$ because more fine Si particles in Al matrix of extrudate at 40$0^{\circ}C$ prevented crack to propagate.

Application of Commercial FEM Code to Coupled Analysis of Casting Deformation (범용 구조해석 프로그램의 주물 열변형 해석에의 적용성)

  • Kim, Ki-Young;Kim, Jung-Tae;Choi, Jung-Gil
    • Journal of Korea Foundry Society
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    • v.22 no.4
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    • pp.192-199
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    • 2002
  • Dimensional defects of castings are mainly due to the stresses and strains caused by a nonuniform temperature distribution and phase transformation during solidification and cooling, and by mechanical constraint between the mold and casting. It is, however, nearly impossible to trace movements of the casting and mold during solidification and cooling by experimental measurements for castings with complex shape. Two and three dimensional deformation analyses of the casting and the mold were performed using commercial finite element code, MARC. It was possible to calculate deformation and temperature distribution in the casting and mold simultaneously. Cooling curves of the casting obtained by calculation were close to that measured in the field since it was possible to treat latent heat evolution of the casting which could be divided into two parts, primary and eutectic parts. Mold bent inward just after pouring due to the temperature gradient across the mold thickness, and mold returned to its previous position with time. Plastic deformation occurred at the part of the casting where solidification was slow.