Tin-nickel plating

Abstract

Electroplating bath for the electrodeposition of tin-nickel alloys, approximating 65% by weight of tin and 35% by weight of nickel, said alloy being deposited over a wide range of current density, from a bath consisting essentially of (i) nickel sulfamate concentrate sufficient to give about 10 ounces of nickel per gallon, and (ii) ammonium bifluoride to the amount of about 1 pound per gallon, and (iii) stannous fluoride sufficient to give about 4 ounces of tin metal per gallon. The bath is strongly self-buffered to a pH 4.3 to 4.5, but operable in the pH range of 4.0 to 5.5. Said bath is operable to place the said amount of tin and nickel at any temperature about 60.degree. C at a current density from 0 up to and exceeding 40 amperes per square foot when temperature is in the range of 74.degree. to 77.degree. C. The deposit is bright, of low compressive stress, and exhibits an extraordinary resistance to corrosion.

Dependencies are inferred from the claim text.