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Chromium-free black zinc-nickel alloy surfaces

  • US 5,393,353 A
  • Filed: 09/16/1993
  • Issued: 02/28/1995
  • Est. Priority Date: 09/16/1993
  • Status: Expired due to Term
First Claim
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1. A method of preparing a black zinc-nickel alloy surface wherein the alloy contains at least about 8% by weight of nickel which comprises contacting said zinc-nickel alloy surface with a chromium-free aqueous acidic solution comprising water, from about 1% to about 10% by weight of a phosphorus acid selected from phosphoric acid, phosphorous acid, hypophosphorous acid and mixtures thereof, and from about 0.1% to about 5% by weight of at least one silane characterized by the formula


  • space="preserve" listing-type="equation">(R.sup.1).sub.a (RO).sub.3-a SiR.sup.2 (IA)
wherein R and R1 are each independently alkyl groups containing from 1 to about 5 carbon atoms, R2 contains from about 1 to about 10 carbon atoms and one or more functional groups selected from the groups consisting of halogen, vinyl, epoxy, acryl, styryl, amino, carboxyl, amide or sulfonyl groups, and a is an integer of from 0 to 3.

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