• 제목/요약/키워드: metallic powder

검색결과 317건 처리시간 0.038초

Cu기 비정질 합금의 과냉각 액상구간에서 온간 압연시 Roll 온도의 영향 (Evolution of temperature gradients during rolling of $Cu_{54}Ni_6Zr_{22}Ti_{18}$ bulk metallic glass in the super cooled liquid region)

  • 박은수;이주호;김휘준;배정찬;허무영
    • 한국소성가공학회:학술대회논문집
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    • 한국소성가공학회 2006년도 춘계학술대회 논문집
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    • pp.409-412
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    • 2006
  • Bulk metallic glass (BMG) strips of $Cu_{54}Ni_6Zr_{22}Ti_{18}$ were produced by warm rolling of the amorphous powder canned with copper. Controlling of temperatures of the rolled sample and rolls was essential for the successive rolling process. Because improper controlling of the sample temperature gave rise to the crystallization of BMG loading to the catastrophic fracture of BMG strips, the temperature of rolls should be properly controlled for achieving successful powder rolling of BMG. The variations of the strain state and temperature in the roll gap was simulated by the finite element method(FEM) using various roll temperatures.

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Kelex100로부터 구리입자 분말 합성 (Composite copper powder from Kelex 100)

  • 조종상;;양권승
    • 한국결정성장학회지
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    • 제8권1호
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    • pp.131-137
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    • 1998
  • 구리입자를 코딩한 분말 합성은 Kelex 100 solvent extraction으로부터 silica powder에 수소압력 stripping copper에 의하여 생성하였다. Solvent extraction의 범위내인 일정한 조건에서 loading level과 stripping rate등을 재생하였으며 stripping copper kinetics는 divalent상태에서 metallic 상태로 감소하면서 silica 입자에 침적하였다. Copper들은 seed 입자에 heterogeneous 핵을 형성하면서 이들은 agglomeration 상태로 생성되었고 불균일한 분말로 형성하였다.

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비행입자의 열 에너지에 따른 NiTiZrSiSn 벌크 비정질 분말의 적층 거동 (Effect of Thermal Energy of In-Flight Particles on Impacting Behavior for NiTiZrSiSn Bulk Metallic Glass during Kinetic Spraying)

  • 윤상훈;김수기;이창희
    • Journal of Welding and Joining
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    • 제25권3호
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    • pp.37-44
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    • 2007
  • Mechanical and thermomechanical properties of the bulk metallic glass (BMG) are so unique that the deformation behavior is largely dependent on the temperature and the strain rate. Impacting behavior of NiTiZrSiSn bulk metallic glass powder during kinetic spraying was investigated in this study. Considering the impact behavior of the BMG, the kinetic spraying system was modified and attached the powder preheating system to make the transition from the inhomogeneous deformation to the homogeneous deformation of impacting BMG particle easy BMG splat formation is considered from the viewpoint of the adiabatic shear instability. It is suggested that the impact behavior of bulk metallic glass particle is determined by the competition between fracture and deformation. The bonding of the impacting NiTiZrSiSn bulk amorphous particle was primarily caused by the temperature-dependent deformation and fracture (local liquid formation) behavior.

착화제 첨가에 따른 웨이퍼 세정 용액 특성 분석 및 금속 용해 거동 (Analysis of Wafer Cleaning Solution Characteristics and Metal Dissolution Behavior according to the Addition of Chelating Agent)

  • 김명석;류근혁;이근재
    • 한국분말재료학회지
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    • 제28권1호
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    • pp.25-30
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    • 2021
  • The surface of silicon dummy wafers is contaminated with metallic impurities owing to the reaction with and adhesion of chemicals during the oxidation process. These metallic impurities negatively affect the device performance, reliability, and yield. To solve this problem, a wafer-cleaning process that removes metallic impurities is essential. RCA (Radio Corporation of America) cleaning is commonly used, but there are problems such as increased surface roughness and formation of metal hydroxides. Herein, we attempt to use a chelating agent (EDTA) to reduce the surface roughness, improve the stability of cleaning solutions, and prevent the re-adsorption of impurities. The bonding between the cleaning solution and metal powder is analyzed by referring to the Pourbaix diagram. The changes in the ionic conductivity, H2O2 decomposition behavior, and degree of dissolution are checked with a conductivity meter, and the changes in the absorbance and particle size before and after the reaction are confirmed by ultraviolet-visible spectroscopy (UV-vis) and dynamic light scattering (DLS) analyses. Thus, the addition of a chelating agent prevents the decomposition of H2O2 and improves the life of the silicon wafer cleaning solution, allowing it to react smoothly with metallic impurities.