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Deposition Of Corrosion And Wear Resistant Coating On High Resistance Substrates

IP.com Disclosure Number: IPCOM000095446D
Original Publication Date: 1964-Jan-01
Included in the Prior Art Database: 2005-Mar-07
Document File: 2 page(s) / 35K

Publishing Venue

IBM

Related People

Koretzky, H: AUTHOR

Abstract

Relatively high current densities are required to electroplate corrosion and wear resistant coatings, such as chromium and rhodium metals. Where the substrate is composed of a thermoplastic sheet having metallic coatings on each side, electroplating such metals onto the substrate would appear impossible. The high current density in a high resistance substrate, such as a thermoplastic, would cause severe ohmic heating and the ultimate destruction of the substrate before the electroplate could be deposited.

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Deposition Of Corrosion And Wear Resistant Coating On High Resistance Substrates

Relatively high current densities are required to electroplate corrosion and wear resistant coatings, such as chromium and rhodium metals. Where the substrate is composed of a thermoplastic sheet having metallic coatings on each side, electroplating such metals onto the substrate would appear impossible. The high current density in a high resistance substrate, such as a thermoplastic, would cause severe ohmic heating and the ultimate destruction of the substrate before the electroplate could be deposited.

An electrodeposit of chromium or rhodium can be made, however, on one side of such a high resistance substrate by use of the phenomenon known as bi- polarity. A standard chromium or rhodium plating solution 10 is placed in container 11. For continuous plating, a length of tape 12 is passed through the plating solution over rollers 13. Tape 12 passes between anode 14 and cathode 15 with its one side directly facing the anode and its other side facing the cathode. Tape 12 can be composed of a film base of polyethylene terephthalate coated on both sides with a nickel-cobalt alloy. Upon closing switch 16, current source 17, connected across electrodes 14 and 15, establishes ionic flow between the electrodes.

The side of tape 12 facing cathode 15 becomes anodic with respect to the tape side facing anode 14. The side of tape 12 facing cathode 15 would thus tend to lose metallic ions to th...