GB1315212A - Electroless nickel and or cobalt plating solutions - Google Patents

Abstract

1315212 Electroless Co and Ni solutions SHIPLEY CO INC 31 July 1970 37086/70 Heading C7F An aqueous Ni and/or Co plating solution comprises a source of Ni and/or Co ions, a hypophosphite reducing agent therefor, a complexing agent therefor, a pH adjuster, and, as stabilizer, mercury ions. A known stabilizer may be added to act synergistically with the mercury ions, which are provided e.g. in amounts of 1-100 ppm., by mercuric acetate, benzoate, bromide, carbonate chlorate, chloride, iodate, nitrate, sulphate or mercuric ammonium chloride; said known stabilizer may be a divalent sulphur compound, e.g. Na 2 S, K 2 S, Na or K polysulphide, NaCNS, KCNS, K 2 S 2 O 6 , Na 2 S 2 O 3 , K 2 S 2 O 3 , thiourea, 2-mercaptobenzothiazole, 1, 2-ethanedithiol, 1, 2-ben zoiso thiazane, methionine, 2, 2'-thiodiethanol, dithioglycol or thiodiglycollic acid, a watersoluble cyanide, e.g. NaCN, KCN, an α-hydroxy nitrile, iminodiacetonitrile, or 3-3'-iminodipropionitrile (trace to 300 ppm.) or R-C#Ch or R'-C#C-R", R, R' and R" being lower monovalent hydroxyalkyl, cydohydroxyalkyl, or hydroxyalkylether, or alkyl or aryl substituted with a water solubilizing group such as -OH or -COOH. The other stabilizer may also be iodate or Pb<SP>++</SP> ion, up to 50 ppm. The mercury is incorporated into the coating. Plastics or cotton cloth is cleaned, sensitized with SnCl 2 /PdCl 2 or else with precious metal/stannic acid colloid, and then electroless plated in the solution.