Cadmium electroplating bath and process
AssigneeMinnesota Mining and Manufacturing Company
InventorsJaan-Jiue Fong, Grace F. Hsu
Life of this patent
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Abstract
An aqueous acidic cadmium electroplating bath containing cadmium ion, sulfuric and/or fluoboric free acid and a surfactant comprised of a combination of a condensed naphthalene sulfonate and a non-ionic polyoxyalkylated compound. Preferably, the bath also contains one or more brighteners.
Claims11
An aqueous electroplating bath for depositing cadmium consisting essentially of about 5 to about 75 grams per liter of cadmium ion, a free acid selected from the group consisting of sulfuric acid, fluoboric acid or mixtures thereof, the concentration of said free acid being from about 0.4N to about 4.0N, from about 0.05 to about 2.0 grams per liter of at least one non-sulfur containing organic brightener compound, and a surfactant combination comprising about 0.5 to about 10.0 grams per liter of a condensed naphthalene sulfonic acid or salt thereof and from about 1.0 to about 20.0 grams per liter of a non-ionic polyoxyalkylated compound.
A method for electroplating cadmium comprising the steps of:
- a. preparing an aqueous bath consisting essentially of about 5 to about 75 grams per liter of cadmium ion, a free acid selected from the group consisting of sulfuric acid, fluoboric acid or mixtures thereof, the concentration of said free acid being from about 0.4N to about 4.0N from about 0.05 to about 2.0 grams per liter of at least one non-sulfur containing organic brightener compound, and a surfactant combination comprising about 0.5 to about 10.0 grams per liter of a condensed naphthalene sulfonic acid or salt thereof and from about 1.0 to about 20.0 grams per liter of a non-ionic polyoxyalkylated compound;
- b. maintaining said bath at a temperature of from about 15.degree. C to about 35.degree. C;
- c. immersing a work piece having a metallic surface and a cadmium anode in said bath;
- and
- d. applying a voltage across said work piece and anode to thereby cause deposition of cadmium on said metallic surface.
Dependencies are inferred from the claim text.