Process for electroplating nickel onto metal surfaces

Abstract

Abstract 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.

Inventors

• 👤 David H Reinert

Bibliographic Details