Improving the voltage holdoff performance of alumina insulators in vacuum by quasimetallizing or doping
Treatment of the surface of an alumina insulator with coatings incorporating varying amounts of Cr, Mn, and Ti can significantly increase the vacuum voltage holdoff capability of the insulator (up to 25 percent). During processing (quasimetallizing) the coating penetrates into the alumina, so it is insensitive to mechanical damage. This quasimetallize treatment is also compatible with subsequent metallizing and brazing of the alumina insulator. Quasimetallizing with appropriate formulations has been shown to change the surface characteristics of alumina in two ways: it decreases both the surface resistivity of the alumina and the secondary electron emission yield of the alumina. Each change improves the voltage holdoff characteristics of the alumina. Similar improvements in voltage holdoff capability can be obtained by doping the plain alumina to the 5 percent (by weight) level with additives of 4 parts Mn/1 part Ti or 2 Mn/1 Ti/1 Cr. Such doped ceramics have the advantage of requiring fewer processing steps than do the quasimetallized ceramics. Both doped and quasimetallized ceramics are suitable for use in ultrahigh vacuum apparatus.
- Research Organization:
- General Electric Co., St. Petersburg, FL (USA). Neutron Devices Dept.
- DOE Contract Number:
- AC04-76DP00656
- OSTI ID:
- 5215696
- Report Number(s):
- GEPP-TIS-476; TRN: 80-013874
- Country of Publication:
- United States
- Language:
- English
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Improving the voltage holdoff performance of alumina insulators in vacuum by quasimetallizing or doping
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Related Subjects
ELECTRICAL INSULATORS
ELECTRIC POTENTIAL
FLASHOVER
ADDITIVES
ALUMINIUM OXIDES
CERAMICS
CHROMIUM
COATINGS
DOPED MATERIALS
MANGANESE
TITANIUM
ALUMINIUM COMPOUNDS
CHALCOGENIDES
CURRENTS
ELECTRIC CURRENTS
ELECTRIC DISCHARGES
ELECTRICAL EQUIPMENT
ELEMENTS
EQUIPMENT
MATERIALS
METALS
OXIDES
OXYGEN COMPOUNDS
TRANSITION ELEMENTS
420800* - Engineering- Electronic Circuits & Devices- (-1989)