Method of electroplating an adherent chromium electrodeposit on a chromium substrate
AssigneeM&T Chemicals Inc.
InventorsHyman Chessin, Warren H. McMullen
Life of this patent
Estimating the term…
Abstract
What is described herein is an improved method of electroplating an adherent chromium deposit on a chromium substrate. The process is characterized by chemically oxidizing the chromium substrate before starting the electrodeposition of chromium thereon. A suitable chemical oxidizing agent is hydrogen ion, which can be furnished by a dilute acid solution. In this invention, the acid is characterized by being destroyed in the plating bath, if dragged therein. Suitable acids include oxalic and citric acids. The process is applicable to any chromium electroplating bath, including high energy efficient chromium baths, such as HEEF-40 baths, which are presently in commercial use.
Claims11
A method of electroplating an adherent chromium deposit on a chromium substrate which comprises the step of chemically oxidizing the chromium substrate by hydrogen ion before electrodepositing chromium from a chromium electroplating bath, said hydrogen ion being furnished by an acid which can be oxidized by chromic acid in said bath to form a gaseous product.
A method according to claim 4 wherein said acid is citric, tartaric, oxalic, glutaric or formic acids.
A method according to claim 10 wherein said oxide film is removed anodically in an electrolyte.
Dependencies are inferred from the claim text.