GB1324827A - Stabilized electroless nickel and or cobalt plating solutions - Google Patents

Abstract

1324827 Electroless Ni and/or Co plating SHIPLEY CO Inc 21 May 1971 [21 May 1970] 16435/71 Addition to 1315212 Heading C7F An aqueous electroless plating solution contains a source of nickel and/or cobalt ions, a reducing agent, a pH adjuster, and as stabilizer, a covalent Hg compound. The reducing agent may be a hypophosphite or a borane; a complexing agent may be present, as may a known stabilizer to co-act with the Hg compound. The Hg compound is preferably R-Hg-R' where R is alkyl, cycloalkyl, aryl, aralkyl, alkaryl, alkoxy, aryloxy or heterocyclic and R' is R or a polar group such as -NO 2 , -SO 2 OH or -SO 2 OM (M is alkali metal) -COOH or -COOM, -NH 2 , -Cl, -Br, -I, -OH or -CN; many examples are given; a preferred amount is 1-100 p.p.m. in the solution. The known stabilizer may be Na 2 S, K 2 S, Na or K polysulphide, a thiocyanate, Na or K thiosulphate, thiourea, 2-mercaptobenzothiazole, 1,2, ethanedithiole, 1, 2-benzoisothiazane, methionine, 2,2'-thiodiethanol dithioglycol, thioglycollic acid, a water-soluble cyanide, e.g. NaCN or KCN, an α-hydroxynitirle iminodiacetonitrile, or 3, 3'-iminodipropionitrile (trace to 300 p.p.m.), an iodate or Pb<SP>+</SP> (< 50ppm) or R<SP>2</SP> - C # CH or R<SP>3</SP> - C # C-R<SP>4</SP> where R<SP>2</SP>, R<SP>3</SP> and R<SP>4</SP> are lower monovalent hydroxyalkyl, cyclohydroxy-alkyl or hydroxyalkyl ether groups or aryl, aliphatic or cyloaliphatic substituted with a water solubilizing group such as -OH or -COOH. Cotton cloth is cleaned, sensitized with SnCl 2 /PdCl 2 or else with a precious metalstannic colloid, and electroless plated with the above solution.