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Method of making low magnetic permeability cobalt sputter targets

  • US 6,176,944 B1
  • Filed: 11/01/1999
  • Issued: 01/23/2001
  • Est. Priority Date: 11/01/1999
  • Status: Expired due to Term
First Claim
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1. A method for manufacturing low magnetic permeability cobalt sputter targets, comprising the steps of:

  • casting a substantially pure cobalt metal having an intrinsic magnetic permeability and slowly cooling the metal at a controlled rate to form a substantially pure cobalt sputter target having a single hexagonal close packed phase;

    hot working the sputter target at a temperature of at least about 1000°

    C. to a strain of at least about 65%;

    slowly cooling the hot worked sputter target at a controlled rate to maintain the single hexagonal close packed phase; and

    cold working the hot worked sputter target at substantially room temperature to a strain of about 5% to about 20%, wherein the cold worked sputter target has a magnetic permeability less than the intrinsic magnetic permeability.

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