Dark colored chromium based electrodeposits
OwnerRoshan V Chapaneri, Richard G Tooth +2inventors
InventorsRoshan V Chapaneri, Richard G Tooth, Roderick D. Herdman, Stacey L. Handy
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Abstract
An aqueous acidic trivalent chromium electrolyte comprising trivalent chromium ions and a complexing agent for maintaining the trivalent chromium ions in solution is provided in which the aqueous electrolyte comprises additives capable of producing a coating on a substrate having a desired dark hue. The additives typically comprise a dispersion of colloidal silica and an additional additive selected from thiocyanate ions and/or iron ions. The electrolyte is used in a method of producing the desired dark-hued decorative chromium coating on a substrate by electrodeposition.
Claims14
A method of producing a chromium coating on a substrate, the method comprising the steps of:
- a) providing a trivalent chromium electrolyte comprising trivalent chromium ions and a complexing agent for maintaining the trivalent chromium ions in solution, wherein the electrolyte further comprises a dispersion of colloidal silica, and
- b) electrodepositing the chromium coating on the substrate using the trivalent chromium electrolyte,
- wherein the chromium coating is produced on the substrate.
Dependencies are inferred from the claim text.