Abstract A method for electrolytic plating of tin-nickel, tin-cobalt or tin-nickel-cobalt on a metal base and acid bath for said plating in which a bivalent salt of tin and nickel or tin and cobalt or tin, nickel and cobalt is dissolved in an aqueous acid bath containing an alkali metal or ammonium fluoride or fluoborate which is reacted with at least about 2 volume percent of an amine to form the fluoride or fluoborate amine salt dissolved in said bath. Preferred amines which form salts are petrylene diamine, diethylene triamine, triethylene tetramine, mono, di or tri ethanolamine and pyridine. Heavy, lustrous ductile coatings are deposited from the bath at pH 3.8 - 5.5 under current intensity of 0.1 - 5 amps/dm2 and at a temperature of 40* - 90*C.
A method as claimed in claim 1 wherein said bath contains ammonium hydroxide in addition to said amine.
Claim 2
Dependent Claim
38 words
A method as claimed in claim 1, wherein said fluoride or fluoroborate salt is formed from an amine selected from the class consisting of ethylenediamine, diethylenetriamine, triethylenetetramine, monoethanolamine, diethanolamine, triethanolamine, N-benzyldiethanolamine, N''-benzyl-N, N-dimethylethylenediamine, N, N-diethylcyclohexylamine, dicyclohexylamine, and tetraethylenepentamine.
Claim 3
Dependent Claim
31 words
A method as claimed in claim 1, wherein said bivalent tin, nickel, cobalt salt are in the bath in the form of their sulfate, sulfonate, chloride, acetate, citrate, or lactate salts.
Claim 4
Dependent Claim
12 words
A method as claimed in claim 1 wherein said pH is 4.8.
Claim 5
Dependent Claim
163 words
An aqueous acid bath at pH 3.8 to about 5.5 containing bivalent water soluble salts of nickel, tin and cobalt in amounts for nickel and cobalt equivalent to 125 to 450 grams per liter as bivalent nickel chloride and 25 to 110 grams per liter as stannous chloride there being also present in said bath the combination of 20 to 100 grams per liter (1) alkali or ammonium fluoride or (2) alkali or ammonium fluoroborate with a non-volatile amine derivative reactive with said fluoride or fluoroborate to form the amine salt thereof, the amine of said amine salt being present in an amount of from 40 to 100 cubic centimeters per liter, said bath adapted for the electrolytic deposition of corrosion resistant tin-nickel, tin-cobalt and tin-nickel-cobalt coatings on a metal base providing by passing current through said bath at an average current intensity between 0.1 to 5 amperes per square decimeter using a nickel anode and providing said metal base as the cathode.