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Electrical Isolation of Copper Thermal Cooling Device by Anodizing an Aluminum Layer On Copper Piston Wall

IP.com Disclosure Number: IPCOM000101358D
Original Publication Date: 1990-Aug-01
Included in the Prior Art Database: 2005-Mar-16
Document File: 2 page(s) / 64K

Publishing Venue

IBM

Related People

Singh, PJ: AUTHOR

Abstract

A structure and a process for fabricating the metallurgically bonded aluminum (Al)/copper (Cu) structure for use as pistons in a thermal conduction device (TCD) is described. The disclosed process meets dimensional precision requirements while providing the piston with both electrical isolation and high thermal conductivity. Fabrication is accomplished in the following four steps: (1) hot isostatically pressing (HIPing) an Al cladding on a Cu rod, (2) cold drawing the rod to a proper diameter accompanied by annealing, (3) machining the Al cladded Cu rod composite into TCD pistons, and (4) masking appropriate Cu surfaces on the piston to anodize the Al.

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Electrical Isolation of Copper Thermal Cooling Device by Anodizing an Aluminum Layer On Copper Piston Wall

       A structure and a process for fabricating the
metallurgically bonded aluminum (Al)/copper (Cu) structure for use as
pistons in a thermal conduction device (TCD) is described.  The
disclosed process meets dimensional precision requirements while
providing the piston with both electrical isolation and high thermal
conductivity. Fabrication is accomplished in the following four
steps: (1) hot isostatically pressing (HIPing) an Al cladding on a Cu
rod, (2) cold drawing the rod to a proper diameter accompanied by
annealing, (3) machining the Al cladded Cu rod composite into TCD
pistons, and (4) masking appropriate Cu surfaces on the piston to
anodize the Al.

      The structure of the Al-clad-Cu TCD piston is shown in the
figure.  A layer 1 of Al is metallurgically bonded to the wall of a
Cu piston 2.  The minimum thickness of the Al layer is dictated a) by
the anodization requirements and b) by the geometry of the part.  The
Al layer 1 is anodized to form an electrically isolating aluminum
oxide layer 3 on the piston's wall.  A plastic cup 4 is inserted into
the spring cavity 5 to physically isolate the spring (not shown) from
the piston 2.

      The process employed to fabricate the anodized aluminum-clad-
copper piston is simple and consists of the following steps:
      a)   A Cu billet is inserted into a close-fitting hollow Al
shell o...