Copper based composite: L-Cop

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Copper based compositeL-Cop
Material Science

• Cu High thermal Conductive
• Cu2O Low thermal expansive

Anna malai Industrial Engineering
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Introduction

• Application
• Electronic devices to achieve long life and
  reliable performance
• High current power modules
• To reduce high shear stress at soldering joint
• Mismatch in coefficient of thermal expansion
  between ceramic substrate to Cu/Al base plate
  attachment
• Silicon carbide reinforced aluminum SiC/Al
• Difficult to machine due to high ceramic content
• Cu/Mo Cu/W Composite
• Difficult to manufacture Sintering at above
  2000C

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L-Cop powder-metallurgy process

• Electrolytic Cu powder and CuO powder are used
• Cu2O is thermally stable than CuO and in elevated
  temperature stable phase of Cu Cu2O can be
  readily achieved in sintering process due to
  internal oxidation of Cu CuO.
• It is possible to distribute the Cu phase and
  Cu2O phase uniformly by Cu CuO Cu2O
  reaction

Fabricated into preform using a press
Ball Milling
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Microstructure in Powder metallurgy process
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Thermal Conductivity Vs. Coefficient of Thermal
Expansion
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Hot Extrusion Process
Improves Heat conductivity, Coefficient of
thermal expansion Density
6500 Mpa Cold Isostatic press Subsequent hot
extrusion.
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Extruded L-Cop Vs. Sintered L-Cop
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Extruded L-Cop application
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References

• www.hitachi-cable.co.jp/en/review/22/pdf/h-13.pdf
• www.howstuffworks.com