Journal of Materials Science

, Volume 12, Issue 6, pp 1095–1104 | Cite as

A scanning electron microscope study of the role of copper oxide layers on arc cathode erosion rates

  • A. H. Hitchcock
  • A. E. Guile
Papers

Abstract

The results are described of scanning electron microscopy of copper surfaces covered initially with oxide films of thickness from 2.5 to 340 nm, which have been the cathodes of electric arcs. The objective of the work has been to learn more about the mechanisms of electrical conduction through oxide films on non-refractory arc cathodes, electron emission into the arc and the erosion of the cathode. It is the latter aspect upon which this paper concentrates. Cathode erosion is a major problem when arcs rotate over electrode surfaces for very long times in certain industrial processes. Erosion rates are calculated here using SEMs, both for stationary 4.5 A arcs of duration 1μec, and for higher current arcs which were magnetically driven once over the cathode surface. Making allowance for the effect of current, these erosion rates are shown to be similar in magnitude and in their variation with oxide thickness, and reasons for this are given. Comparison is then made with erosion rates measured by weight loss for long-duration rotating arcs. In the light of the new data given here, it is now possible to understand better the remarkable changes which have occurred for long-duration arcs when varying arc velocity, water-cooling flow rate and arcing duration.

Keywords

Erosion Rate Oxide Film Electron Microscope Study Copper Oxide Electron Emission 

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Copyright information

© Chapman & Hall Ltd. 1977

Authors and Affiliations

  • A. H. Hitchcock
    • 1
  • A. E. Guile
    • 1
  1. 1.Department of Electrical and Electronic EngineeringUniversity of LeedsLeedsUK

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