ELECTROLYTIC PROCESS AND ELECTROLYTIC BATH FOR PRECIPITATION OF TIN/NICKEL/TIN/COBALT OR TIN/NICKEL/COBALT LAYERS

摘要

1396540 Electrolytic deposition of Sn/Ni, Sn/Co or Sn/Ni/Co BERGISCHE METALLWARENFABRIK DILLENBERG & CO KG 20 July 1972 [21 Aug 1971] 33997/72 Heading C7B Sn/Ni, Sn/Co or Sn/Ni/Co layers are electrolytically deposited from a bath containing a Sn salt together with a Ni salt and/or a Co salt and also the fluoride or fluoborate salts of one or more amines, the amine(s) being present in a total amount of at least 10 g/l and up to 100 g/l. Many suitable fluoride and fluoborate salts of amines are specified amongst which are the salts of ethylenediamine, diethylene triamine, triethylene tetramine mono-, di- and/or triethanolamine, 2-ethylaminoethanol, N-benyldiethanolamine, bis-(2-ethoxyethyl)-amine, dicyclohexylamine, melamine and tricyanomethylamine. Specified Sn, Ni and Co salts for the bath are the sulphates, sulphonates, chlorides, acetates, citrates and lactates. The bath may contain HCl. The pH may be adjusted to between 3À8 and 5À5 by the amine and/or by ammonia. Electrolytic deposition may be carried out at between 40 and 90 C at a current density between 0À1 and 5 amps/dmSP2/SP using a sheet Ni anode. In the Examples the fluoride or fluoborate salt of the amine is derived from NH4F.HF or NH 4 BF 4 . A workpiece may be Ni plated before depositing the Sn/Ni. Bodies of Fe may be directly plated with the Sn/Ni, Sn/Co or Sn/Ni/Co. Bodies of Fe, steel, Cu, Ni and brass can be coated directly with Sn/Ni but bodies of die cast Sn or Al are Cu coated first. Coating Sn/Ni on to brass cans, Fe camera housings and bottle openers, die cast Sn door handles, Al fruit juice presses, steel electric devices and printed circuits is referred to.