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Testing Porosity in Palladium Plated Nickel Articles

IP.com Disclosure Number: IPCOM000091013D
Original Publication Date: 1969-Sep-01
Included in the Prior Art Database: 2005-Mar-05
Document File: 2 page(s) / 48K

Publishing Venue

IBM

Related People

Hagstrom, RA: AUTHOR

Abstract

One or more test articles located within sample basket 10 are placed within test chamber 11. The latter is evacuated through port 12 and heated by induction coil 13, or the like, connected to power supply 14. As an alternate, chamber 11 can be inserted into a muffle furnace heated to the required temperature. When the temperature of chamber 11 reaches at least 900 degrees F, and preferably 1200 degrees F, a supply of sulphur dioxide gas is introduced into it through inlet 15. The test parts are exposed for approximately five minutes to the heated sulphur dioxide. The time of exposure varies somewhat depending on the size of the test articles. The optimum time and temperature for various types of articles can be determined empirically.

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Testing Porosity in Palladium Plated Nickel Articles

One or more test articles located within sample basket 10 are placed within test chamber 11. The latter is evacuated through port 12 and heated by induction coil 13, or the like, connected to power supply 14. As an alternate, chamber 11 can be inserted into a muffle furnace heated to the required temperature. When the temperature of chamber 11 reaches at least 900 degrees F, and preferably 1200 degrees F, a supply of sulphur dioxide gas is introduced into it through inlet 15. The test parts are exposed for approximately five minutes to the heated sulphur dioxide. The time of exposure varies somewhat depending on the size of the test articles. The optimum time and temperature for various types of articles can be determined empirically. After heating, the test articles are metallographically polished and the diffusion of sulphur in the nickel substrate is determined. The operation of this test is based on the fact that solid palladium, when heated, passes no gas other than hydrogen and that nickel is attacked intergranularly by sulphur at temperatures over 900 degrees F, Inasmuch as sulphur dioxide cannot diffuse through solid palladium, the depth of diffusion for a predetermined time and temperature within the nickel substrate is directly related to the amount of sulphur absorbed by the nickel in porous areas, and is, therefore, an indication and measure of amount of porosity in the plating. The method can be us...