GB1249002A - Improvements in or relating to nickel metal or nickel alloy plating - Google Patents

Abstract

1,249,002. Electro-depositing micro-porous. chromium on prepared nickel plate. M & T CHEMICALS Inc. May 27, 1969 [June 17, 1968], No. 26685/69. Heading C7B. A Ni or Ni alloy (e.g. Ni-Co) plated article receptive to a decorative micro-porous and cracked Cr plate is prepared by affixing to a basis material bearing a metal surface a stratum of particles of 0‹05-15 micron size and density of 100-5, 000, 000 particles/sq cm of metal surface, and depositing in the stratum of particles a Ni or Ni alloy layer having a tensile stress of at least 8, 400 (e.g. to 14, 000) kg/sq cm and an effective thickness (e.g. of 0‹1-1À0 micron) less than the maximum thickness of the stratum, to form a matrix wherein particles are retained affixed to the surface in the layer and at least some of the particles intercept the layer surface. The basis material may be metallic, e.g. Fe, steel, brass, bronze, Cu, Zn, Al, Mg, Ni metal or alloy; or plastic, e.g. A-B-S resin, acetals, acrylics, alkyds, allyls, amines, cellulosics, chlorinated polyethers, epoxys, furanes, fluorocarbons, isocyanates (urethanes) polyamides (nylons), phenoxys, phenolics, polycarbonates, polyesters, polyethylenes, polypropylines, silicones, polystyrenes, polyvinyls or copolymers thereof, rendered conductive e.g. by a Ni deposit. Preferably metallic basis material, e.g. steel, Zn or brass, is initially plated with Cu, bronze or semi-bright Ni, followed with a bright Ni plate. After cathodically cleaning in alkaline cleaner and water or acid rinsing, the basis metal is preferably given a Ni flash or strike 0À6-1À8 microns thick by electro-deposition from a NiCl 2 -NiSO 4 - HCl bath; then a bright Cu plate 0À8-24 microns thick from a CuSO 4 -H 2 SO 4 bath with additives including polyoxyethanols, aldehyde, thiazolidine thione, mercaptothiazoline, N-(2-hydroxyethyl) ethylene thiourea, y, γ<SP>1</SP> -thio dipropyl sulphonate di-2-(7-sulphonate naphthyl) methane, 2, 4, 7, 9- tetramethyl-4-7-di (hydroxy, polyethoxy), decyn-5; followed by semi-bright (e.g. 12À5 microns thick) and bright (e.g. 7À5 microns thick) plates electrodeposited from a Watts, chloride or chloride-free sulphamate, hyrophosphate or fluoborate bath, examples of which are specified. Brighteners and wetting agents in these baths include K 6- sulpho-w-propyl coumarin, Na dihexyl sulphosuccinate, butyne 1, 4-diol, tris-cyanoethyl- 2-thiohydantoin, and Na lauryl sulphate. The particles may be spherical to elongated, angular or platelet-shaped, and may be affixed by blowing the particles over the metal surface, by dipping the basis material intc a fluidized bed of the particles, or by electro-static or electro-phoretic depositing. Particles of talc, kaolin, wax, graphite, MoS 2 , WS 2 , pigments (e.g. barytes, Cr-Co green, Co-Al blue), SiO 2 , Al 2 O 3 , plastic (e.g. polymers or copolymers of styrene, butadiene, acrylonitrile, vinyl acetate and chloride), diatomite, Al, activated C, Na 2 SiO 3 , CaCO 3 , carbides and/or S may be used. Additives such as amides, amines, alcohols or acetylinics may be present. The particles may be suspended in a concentration of 0À1-1% in a water, nickelplating or latex bath which may include surfactants, dispersants, thixotrophes, emulsifiers, e.g. alginates, lignosulphonates, gelatine, hydroxy ethyl cellulose and/or dimethyl oleamide, and electrolytes, e.g. Na 2 SO 4 , heavy metal salts or acids. Many resin and rubber latex baths are specified. Electro-plating baths for depositing the high stress Ni (alloy) layer (e.g. 0À02-3 microns thick) may contain (in g/l): (1) 110-225 NiCl 2 -6H 2 O, 300-900 Ni(BF 4 ) 2 , 0À002-0À4 primary brightener e.g. butyne diol, 0À1-1 secondary, brightener e.g. saccharin and 0À1-0À8 additive heterocyclic compound having at least 2N in an otherwise carbocyclic ring, preferably hexamethylene tetramine, pyrazine, 2, 6-dimethyl pyrazine or 1:1<SP>1</SP> ethylene 2:21 dipyridinium dichloride; many other brighteners and additives are specified. (2) 60-400 NiSo 4 6H 2 O, 1À6-13À5 NH 4 + , 13-45 H 3 BO 3 and 0À2-0À8 brightener acetylenic compound; numerous compounds are specified. (3) 200-400 NiSO 4 6H 2 O, 30-75 NiCl 2 6H 2 O, 2À5-145 CoSO 4 7H 2 O, 30-50 H 3 BO 3 , 0À5-1À0 (NH 4 ) 2 SO 4 , 1À5-4À0 formaldehyde and 30-60 nickel formate. The final Cr plate (e.g. 0À02-5 micron thick) may be electro-deposited from a bath containing CrO 3 (e.g. from Na 2 Cr 2 O 7 ) and SO 4 -- (e.g. from Na 2 SO 4 or SrSO 4 ), with or without SiF 6 -- (e.g. from Na 2 SiF 6 ).