Surface studies of Os/Re/W alloy-coated impregnated tungsten cathodes

Journal Article · Tue May 01 00:00:00 EDT 1990 · Journal of Vacuum Science and Technology, A (Vacuum, Surfaces and Films); (USA)

DOI:https://doi.org/10.1116/1.576758· OSTI ID:6901744

Ares Fang, C S ^[1]; Maloney, C E ^[2]

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1. Institute of Physics, Academia Sinica, Taipei 11529, Taiwan, Republic of China (TW)
2. Engineering Department, Cambridge University, Cambridge CB2 1PZ (United Kingdom)

Impregnated tungsten cathodes half-coated with Re/W (or Os/W) alloy and Os/Re/W alloy at right angles were studied to compare the effects of Os/Re/W alloy coatings on the electron emission and emission mechanisms. Constant surface metal compositions of 32% Os--29% Re--39% W and 35% Os--26% Re--39% W were obtained from the activated surfaces initially coated with 40% Os--40% Re--20% W and 35% Os--45% Re--20% W alloys, respectively. Thermionic emission microscopy measurements showed that the Os/Re/W alloy-coated surface gives an average effective work function of 0.29, 0.08, and 0.03 eV lower than the uncoated, Re/W and Os/W alloy-coated surfaces. An effective work function of 1.73 eV was obtained from an activated Os/Re/W alloy surface. Auger studies exhibited a smaller BaO coverage and a higher barium coverage in excess of BaO stoichiometry on the Os/Re/W alloy-coated surface compared to the uncoated, Re/W and Os/W alloy-coated surfaces.

• OSTI ID: 6901744
• Journal Information: Journal of Vacuum Science and Technology, A (Vacuum, Surfaces and Films); (USA), Journal Name: Journal of Vacuum Science and Technology, A (Vacuum, Surfaces and Films); (USA) Vol. 8:3; ISSN JVTAD; ISSN 0734-2101
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
360104* -- Metals & Alloys-- Physical Properties
ALLOY SYSTEMS
ALLOYS
AUGER ELECTRON SPECTROSCOPY
BINARY ALLOY SYSTEMS
CATHODES
COATINGS
DEPOSITION
ELECTRODES
ELECTRON SPECTROSCOPY
EMISSION
FUNCTIONS
OSMIUM ALLOYS
PLATINUM METAL ALLOYS
RHENIUM ALLOYS
SPECTROSCOPY
THERMIONIC EMISSION
TUNGSTEN ALLOYS
WORK FUNCTIONS