This invention overcomes problems such as pinholes and blisters in making plated coin blanks and similar articles. A ferrous metal blank is electroplated with a strike of nickel, following which a coating of copper is applied at an initial low current density followed by full current density to minimize bridging. The low current density may be about 1/6 to 1/4 of the full current density. Preferably an outer layer of nickel is applied, also at an initial low current density, followed by full current density. Annealing before or after application of the final layer of nickel is advisable. This invention also relates to the resulting coin blank and coins.

Coins coated with nickel, copper and nickel and process for making such coins

An anti-scratch nickel plated steel sheet and strip is provided which comprises, applying a nickel plating to both sides of the sheet or strip, subsequently plating a nickel phosphorus alloy on at least one or the other side of said plated layer, then subjecting said plated article to a heat treatment under conditions sufficient to form a nickel ferrous alloy layer and to obtain a hardening effect of said nickel phosphorus alloy plated layer.

Scratch and corrosion resistant, formable nickel plated steel sheet, and manufacturing method

A composite article includes a compressively stressed plating which provides increased static strength and fatigue life. In particular, a fan exit guide vane (1), made of a graphite fiber reinforced composite material and including a conductive plating (7), achieves a 380% increase in static load capability over an unplated composite vane and a low cycle fatigue life of over 1 million cycles through the application of a compressively stressed nickel plating (8) which produces a residual compressive stress state of between -5,000 and -15,000 psi.

Fatigue strengthened composite article

A metal matrix composite lightweight compressor airfoil. The airfoil comprises a braided fabric embedded in a lightweight aluminum-lithium alloy. The airfoils are fabricated by forming a plurality of fiber tows by twisting filaments or fibers. The tows are then braided into a fabric. The fabric may be impregnated with an optional fugitive polymer that temporarily occupies interstices of the fabric to facilitate handling of the pre-formed braided fabric, but which is subsequently removed. The airfoil may then be formed as a MMC by one of two separate methods. In the first method, aluminum-lithium alloy is pressure augmented casting into a die that includes a preform of fabric impregnated with fugitive polymer. In a second method, a preform is formed using a tool and mandrel by impregnating fabric with aluminum-lithium alloy. Then aluminum-lithium alloy is pressure augmented cast into a die that includes the alloy-impregnated preform.

FIBER REINFORCED Al-Li COMPRESSOR AIRFOIL AND METHOD OF FABRICATING

A process for metal plating a stainless steel comprising the first step of treating the stainless steel by a cathode electrolysis in an aqueous solution containing free HCl in an amount at least 30 g/l and at least one species of Ni and Co in an amount at least 0.1 g/l; the second step of metal plating the same by Ni or a Ni alloy in a weakly acidic Ni plating bath; and the third step of subsequently plating the same by a noble metal, Cu or an alloy thereof.

Process for metal plating a stainless steel

AN ADHERENT, WEARABLE NICKEL COATING IS APPLIED TO A METAL SURFACE BY A MULTISTEP PROCESS IN WHICH THE METAL SURFACE IS (A) SUBJECTED TO AN ANODIC CURRENT DENSITY IN AN AQUEOUS ACID TREATMENT BATH, PREFERABLY CONTAINING SULFURIC ACID IN AN AMOUNT BETWEEN ABOUT 20 AND 30% BY VOLUME, AT A BATH TEMPERATURE OF 40 TO 85*F. AND A CURRENT DENSITY OF 75 TO 250 A.S.F.; (B) COATED WITH A THIN NICKEL BASE COAT BY MEANS OF A NICKEL STRIKE APPLIED FROM AN ELECTROPLATING BATH PREFERABLY CONTAINING 30 TO 34 OZ./GAL. OF NICKEL CHLORIDE AND 9 TO 12% BY VOLUME OF HYDROCHLORIC ACID, AND UTILIZING A 99% MINIMUM PURITY NICKEL ANODE AND A CATHODIC CURRENT DENSITY BETWEEN ABOUT 50 AND 100 A.S.F., AND (C) THEN APPLYING A NICKEL COATING OF THE DESIRED THICKNESS TO THE METAL SURFACE IN A NICKEL SULFAMATE PLATING BATH MAINTAINED AT A TEMPERATURE OF 110 TO 125*F. AND AT A PH OF 3.5 TO 4.2. THE NICKEL SULFAMATE PLATING BATH PREFERABLY CONTAINS 62 TO 66 OZ./ GAL. OF NICKEL SULFAMATE (27 TO 31*BE.), 0.7 TO 2.0 OZ./GAL. NICKEL CHLORIDE, 4 TO 5 OZ./GAL. BORIC ACID, 1 TO 3 OZ./GAL. NAPHTHYLENE TRISULFONIC ACID, AND A SUFFICIENT QUANTITY OF AN ORGANIC WETTING AGENT TO MAINTAIN THE BATH SURFACE TENSION AT BETWEEN ABOUT 20 AND 60 DYNES/CM.2. A 99% MINIMUM PURITY NICKEL ANODE IS USED IN THE NICKEL SULFAMATE PLATING BATH AND PLATING IS CARRIED OUT AT A CURRENT DENSITY PREFERABLY BETWEEN 60 AND 100 A.S.F. THIS PROCESS CAN BE APPLIED TO VARIOUS METAL SURFACES INCLUDING COPPER, BRASS AND BOTH HIGH AND LOW CARBON STEELS. THE RESULTANT ARTICLE HAS AN ADHERENT, WEARABLE NICKEL COATING HAVING AN EXCELLENT COMBRINATION OF HARDNESS, DUCTILITY AND COMPRESSIVE STRESS PROPERTIES.

David H Reinert

Papers

Process for electroplating nickel onto metal surfaces