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Coating of Gold Wires by Electrophoresis

IP.com Disclosure Number: IPCOM000090019D
Original Publication Date: 1969-Jan-01
Included in the Prior Art Database: 2005-Mar-05
Document File: 1 page(s) / 11K

Publishing Venue

IBM

Related People

Bell, HF: AUTHOR

Abstract

Bromide ions in the coating bath lessen the sponginess of a polymer film deposited by electrophoresis on wires composed of a noble metal such as gold. Sponginess is attributed generally to voids produced by evolution of oxygen at the noble metal electrode and diffusion through the deposit. Oxygen evolves from the anodic dissolution of the solvent.

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Coating of Gold Wires by Electrophoresis

Bromide ions in the coating bath lessen the sponginess of a polymer film deposited by electrophoresis on wires composed of a noble metal such as gold. Sponginess is attributed generally to voids produced by evolution of oxygen at the noble metal electrode and diffusion through the deposit. Oxygen evolves from the anodic dissolution of the solvent.

A bath of 3 parts by volume water and 1 part by volume resin dispersion is used. The resin is a 60/40 weight percent mixture of TEFLON* 30B and HYCAR* 1561. Potassium bromide 8;10% by weight is added. The solution is prepared by dissolving the potassium bromide in one-third of the water and adding the TEFLON/AYCAR to the remaining two-thirds of water. The two solutions are mixed with constant stirring.

The gold or other noble metal to be coated is cleansed thoroughly with trichloroethylene. Deposition is carried out in apparatus described in the IBM Technical Disclosure Bulletin, Vol. 10, pg. 683. Voltages between 1.5 and 2.0 volts yield satisfactory coatings. Without rinsing the coatings are air dried for one hour and oven dried at 160 degrees F overnight. The bromide ions reduce oxygen evolution by permitting deposition of the polymer at voltages below the potential at which the solvent begins to oxidize. * Trademark of E. I. du Pont de Nemours and Co. ** Trademark of B. F. Goodrich Chemical Co.

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