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Bonding Lanthanum Hexaboride to Copper

IP.com Disclosure Number: IPCOM000089991D
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

Cuomo, JJ: AUTHOR [+3]

Abstract

The method bonds lanthanum hexaboride electron emissive cathodes to copper heat sinks. The lanthanum hexaboride is first cleaned in acetone and then ethyl alcohol for degreasing. After degreasing, that portion of the lanthanum hexaboride where bonding is desired is etched in a 1 part concentrated nitric acid to 1 part deionized water for 5 to 10 seconds. Then the etched region is rinsed with deionized water and then ethyl alcohol. After being blown dry with nitrogen, the etched region is electroplated with a .05 mil to .2 mil layer of nickel to accommodate brazing. That portion of the copper where bonding is to occur is cleaned and then pretreated with a 10% to 20% solution of sulfuric acid for approximately 2 minutes.

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Bonding Lanthanum Hexaboride to Copper

The method bonds lanthanum hexaboride electron emissive cathodes to copper heat sinks. The lanthanum hexaboride is first cleaned in acetone and then ethyl alcohol for degreasing. After degreasing, that portion of the lanthanum hexaboride where bonding is desired is etched in a 1 part concentrated nitric acid to 1 part deionized water for 5 to 10 seconds. Then the etched region is rinsed with deionized water and then ethyl alcohol. After being blown dry with nitrogen, the etched region is electroplated with a .05 mil to .2 mil layer of nickel to accommodate brazing. That portion of the copper where bonding is to occur is cleaned and then pretreated with a 10% to 20% solution of sulfuric acid for approximately 2 minutes. The electroplated portion of the lanthanum hexaboride is then brazed to the copper heat sink by melting a copper-silver eutectic alloy in a hydrogen furnace until the alloy flows. Alternatively, a palladium-silver or nickel-gold alloy can be used in place of the copper-silver alloy.

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