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ELECTRO-POLISHING OF ELECTRICAL CONTACTS

IP.com Disclosure Number: IPCOM000024728D
Original Publication Date: 1981-Dec-31
Included in the Prior Art Database: 2004-Apr-02
Document File: 2 page(s) / 92K

Publishing Venue

Xerox Disclosure Journal

Abstract

Precious metals such as silver, gold and platinum are used as either solid alloys or platings for electrical contacts and terminals. These materials are used due to their high electrical conductivity and their ability to resist formation of insulating metal oxide and sulfide films. In contacts which are not usually used to make and break electrical loads, such as connector terminals, precious metals are used only for low energy level circuits which have particular difficulty in breaking through films. Terminals used for conducting higher energy levels are usually non-precious metal. These terminals are usually bare brass or copper alloys such as phosphorous bronze or beryllium copper or one of these materials with a tin or tin alloy plating. Switching contacts usually utilize gold and platinum and silver-cadoxide alloys for higher energy circuits. With the increasing price of precious metal, it is becoming more and more important to find a way to obtain better performance from non-precious metal terminals and terminal platings or even to improve the performance of lower cost precious and semi-precious metals such as silver, palladium and nickel. This applies not only to connector terminals, but also to switch and relay contacts.

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XEROX DISCLOSURE JOURNAL

ELECTRO-POLISHING OF ELECTRICAL Proposed Classification CONTACTS U.S. C1. 29/874
Paul G, Feil Int. C1. B23p 19/00

Precious metals such as silver, gold and platinum are used as either solid alloys or platings for electrical contacts and terminals. These materials are used due to their high electrical conductivity and their ability to resist formation of insulating metal oxide and sulfide films. In contacts which are not usually used to make and break electrical loads, such as connector terminals, precious metals are used only for low energy level circuits which have particular difficulty in breaking through films. Terminals used for conducting higher energy levels are usually non-precious metal. These terminals are usually bare brass or copper alloys such as phosphorous bronze or beryllium copper or one of these materials with a tin or tin alloy plating. Switching contacts usually utilize gold and platinum and silver-cadoxide alloys for higher energy circuits. With the increasing price of precious metal, it is becoming more and more important to find a way to obtain better performance from non- precious metal terminals and terminal platings or even to improve the performance of lower cost precious and semi-precious metals such as silver, palladium and nickel. This applies not only to connector terminals, but also to switch and relay contacts.

There may be some significant strides made in this direction by use of a process known as electro-polishing. This process is essentially a reverse electro-plating process. Improvement in performance can be expected for several reasons.

(1) The process tends to passivate metal surfaces by removing more active metals from the surfaces and pores of the base metals. (2) The process...