Acid zinc electroplating bath and process
AssigneeMinnesota Mining and Manufacturing Company
InventorsGrace F. Hsu, Jaan-Jiue Fong
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Abstract
An aqueous, ammonium ion-free acid zinc electroplating solution comprising a source of zinc ion, a soluble electrolyte, boric acid, a non-ionic polyoxyalkylated surfactant, and an organic acid, the bath being operable at a pH of about 3.0 to about 6.5. Preferably, the bath also contains a brightener. Spent baths are simply and inexpensively disposed of.
Claims7
An aqueous ammonium ion-free electroplating bath for depositing zinc comprising about 4.0 to about 100.0 grams per liter of zinc ion, from about 15.0 to about 250.0 grams per liter of an ammoniumfree electrolyte, from about 2.0 to about 40.0 grams per liter of a non-ionic polyoxyalkylated compound selected from the group consisting of alkoxylated alkyl phenols, alkoxylated alkyl naphthols, alkoxylated aliphatic monohydric alcohols, alkoxylated polyoxypropylene glycols, alkoxylated 2,4,7,9-tetramethyl-5-decyne-4,7-diol, alkoxylated ethylene diamine, alkoxylated fatty acids, alkoxylated amides, and alkoxylated esters, from about 0.1 to about 15.0 grams per liter of a carboxylic acid, and at least about 1.0 grams per liter of boric acid or a soluble salt thereof, the pH of said bath being from about 3.0 to about 6.5.
A method for electroplating zinc comprising the steps of:
- a. preparing an ammonium ion-free aqueous bath comprising about 4.0 to about 100.0 grams per liter of zinc ion, from about 2.0 to about 40.0 grams per liter of a non-ionic polyoxyalkylated compound selected from the group consisting of alkoxylated alkyl phenols, alkoxylated alkyl naphthols, alkoxylated aliphatic monohydric alcohols, alkoxylated polyoxypropylene glycols, alkoxylated 2,4,7,9-tetramethyl-5-decyne-4,7-diol, alkoxylated ethylene diamine, alkoxylated fatty acids, alkoxylated amides and alkoxylated esters, from about 0.1 to about 15.0 grams per liter of a carboxylic acid, and at least about 1.0 gram per liter of boric acid or a soluble salt thereof;
- b. maintaining said bath at a temperature of from about 15.degree. C to about 45.degree. C and a pH of from about 3.0 to about 6.5;
- c. immersing a work piece having a metallic surface and a zinc anode in said bath;
- and
- d. applying a voltage across said work piece and anode to thereby cause deposition of zinc on said metallic surface.
Dependencies are inferred from the claim text.