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Forming Small Diameter Tips on Sintered Material Cathodes

IP.com Disclosure Number: IPCOM000074913D
Original Publication Date: 1971-Jun-01
Included in the Prior Art Database: 2005-Feb-24
Document File: 2 page(s) / 35K

Publishing Venue

IBM

Related People

Broers, A: AUTHOR

Abstract

This is a method for forming extremely small diameter tips on the ends of electron-emitting cathodes, consisting of normally sintered material such as lanthanum hexaboride rod cathodes.

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Forming Small Diameter Tips on Sintered Material Cathodes

This is a method for forming extremely small diameter tips on the ends of electron-emitting cathodes, consisting of normally sintered material such as lanthanum hexaboride rod cathodes.

One end 17 of the lanthanum hexaboride rod 16 is melted by an electron beam heating technique using an electron or laser beam source 14 in order to produce a dense fused mass at the end of the rod, allowing the melted portion to resolidify and subsequently polishing the dense end of the rod to a size of about one micron in diameter. The electron beam source 14 and rod 16 are arranged in an evacuated chamber 12 and the energy beam is directed axially toward the end of the lanthanum hexaboride rod. After the melted portion has resolidified, the approximate tip geometry may be obtained by a suitable spark machining process, and subsequently the fine tip 21 may be achieved by fine polishing techniques, at B.

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