The field enhancement factor of sand-blasted electrodes

A sample of six sand-blasted electrodes has been subjected to both mechanical and electrical investigations. When the surfaces of a series of conductors are mechanically treated, the resultant microscopic surface geometries will be similar, but not identical. As a consequence of this spread in the geometric characteristics of the roughened surfaces, the m values associated with nominally identical conductors will also exhibit a scatter. The method, which is based on the detection of discharge onset in a gaseous medium at the surface in question, was used to investigate the scatter in a field enhancement factor m for a particular surface treatment. For the sample studied, the mean electric field enhancement factor was found to be 6.6. The mechanical surface parameters indicated a sand aging effect