Burlington Industries, Inc.

Nancy E Myers

Rodger L Gamblin

David J Sugg

John A Lichtenberger

An anode configuration is provided particularly for a bath that is used for electrolytically plating a substrate with a nickel and/or cobalt phosphorus alloy. The anode comprises a plurality of widely spaced portions of material, preferably of platinum or rhodium. The anode configuration is such that the anode has a very high current density in use--at least 200 amperes per square foot and preferably 500 amperes per square foot. The wide spacing of the anode portions may be provided in a number of different ways. A platinum wire may extend between titanium screws attached to a pair of parallel spaced titanium buses, in a zig-zag manner. A platinum wire may be welded at its opposite ends to a titanium bus, and helically wrapped around the bus, with the welding junctions covered by an insulating material (e.g. vinyl). A platinum tube may be shrink fit onto a titanium bus.

Anode configuration for nickel-phosphorus electroplating

An all chloride bath is provided for electroplating nickel phosphorus on a substrate. The bath includes 0.7-1.3 molar Ni.sup.+, 1-2 molar Cl.sup.-, and 1-3 molar HPO.sub.3.sup.+2. The bath also optionally contains 0.2-0.6 molar PO.sub.4.sup.-3. The bath contains as little sulfate as possible. Any sodium lauryl sulfate in the bath can be removed using a carbon filter. The electroplatings produced according to the invention have Knight shift, density, and non-uniform thickness properties more characteristic of electroplated nickel phosphorus than electroless. They have lower tensile strength, increased inherent brightness, and reduced graininess compared to electroplating from baths including sulfate. The bath has increased cathode efficiency, increased conductivity, and reduced formation of unwanted precipitates compared to baths with sulfates. The bath constituents may be provided from NiCl.sub.2.6H.sub.2 O and H.sub.3 PO.sub.3 ; or from Ni(H.sub.2 PO.sub.3).sub.2 and HCl.

Nickel-phosphorus electroplating and bath therefor

A plating bath for nickel and/or cobalt phosphorus amorphous alloy coating can last almost indefinitely. The anode current density of the bath is controlled so as to maintain the amount of phosphoric acid in the bath constant, and less than a level (e.g. around 0.5 molar) at which it has significant deleterious effects on the bath, i.e. maintaining the free acid concentration in the bath in an acid titer range of about 9-14. The anode current density is maintained at about 200 amperes per square foot or greater, and preferably about 500 amperes per square foot or greater, by employing an anode construction that comprises a plurality of widely spaced strips (e.g. wires) of platinum or rhodium; e.g. platinum wires each having a diameter of about 0.010 inches and, for example, a length of about 3.2 inches, and disposed vertically and generally parallel to, but spaced from, a face of a cathode-workpiece that is to be plated with nickel phosphorus, cobalt phosphorus, or nickel/cobalt phosphorus. The anode alternatively may comprise a wire extending in zig-zag fashion between a pair of spaced bus bars. The methods according to the invention are particularly useful for plating fluid jet orifice plates, electrical contacts, carbon steel or stainless steel cutlery, aluminum articles, cookware substrates (such as aluminum, stainless steel, copper, iron, or cast iron substrates), magnetic or magnetizable material such as computer memory storage discs, and wear surfaces such as thrust bearings, shafts for high speed machinery, or the like.

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Kettering, OH, United States of America

Nancy E Myers