Electrodeposition of chromium
AssigneeInternational Business Machines Corporation
InventorsDonald John Barclay, William Morris Morgan
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Abstract
Chromium containing deposits free of cracks and having good hardness are plated by the use of a novel aqueous chromium (III) electrolyte. The electrolyte includes an aquo chromium (III)-thiocyanato complex as a source of chromium (III) cations.
Claims24
A composition of matter for use in the electrodeposition of chromium containing deposits consisting essentially of an aqueous solution of aquo chromium (III) thiocyanato complex as a source of trivalent chromium, the concentration of the Cr (III) being in the range of 0.03 to 0.5 M.
A method of electrodepositing chromium containing material on a cathode, which comprises passing an electroplating current between an anode and said cathode in a plating solution consisting essentially of an aqueous solution of an aquo chromium (III) thiocyanato complex as a source of trivalent chromium.
The method of preparing a plating solution for electroplating of chromium comprising the step of reacting a thiocyanate anion with chromium perchlorate in the presence of boric acid in an aqueous solution having a pH of 1 to 2 to form an aquo chromium III thiocyanato complex of the formula (H.sub.2 O).sub.6-n Cr(SCN).sub.n.sup.(+3-n), which n is a whole number from one through six.
Dependencies are inferred from the claim text.