STUDIES ON BASE NICKELS FOR OXIDE-COATED CATHODES
Abstract
Studies of the relationship between chemical reduction and thermionic activity of an oxide cathode were continued. Results are presented for oxide cathodes based on carbon-Ni diffusion throttles. It is postulated that a process involving a surface transport path can account for the observed behavior. Further studies are reported on the controlled reduction of an oxide cathode, applying a carbon source in a separate vacuum enclosure to the back face of the cathode base. The steady-state pulse emission appears to be proportional to the square root of the steady-state reduction rate. Cathodes, based on 0.2% and 0.08% Al-Ni alloys, have now operated at 1093 K for about 16,500 hr. Space-charge limited currents in excess of 11 amps/sq cm continue to be observed in all cases. The influence of the coating thickness on cathode properties was investigated. Both the saturation emission and coating conductivity increase monotonically with coating thickness over this range. The effects of heated anodes on oxide cathodes, photoelectric measurements of oxide coatings and thin films, and an analysis of the expected thermal transients in an oxide coating underlong-pulse current drain are also reported. (Author)
Document Details
- Document Type
- Technical Report
- Publication Date
- Jan 15, 1961
- Accession Number
- AD0259059
Entities
People
- D.e. Anderson
- W.g. Shepherd
Organizations
- University of Minnesota