Surface chemical changes of polymer cavities with currents aboveand below corona inception voltage

摘要

X-ray photoelectron spectroscopy, (XPS) has been used to followthe chemical changes that occur with applied voltage on the walls ofcavities in polyethylene (PE). These cavities simulate voids found incommercial insulation. A wide range of current, time, and appliedvoltages above and below the corona inception voltage (CIV) have beenexplored. The XPS analysis area is much less than 1 mm2 withthe cavities in roughly the same size regime. During the XPS datacollection, mass spectrometric analyses were made of evolved gases fromthe samples. Experimental techniques for the control of chemical purity,chemical analysis, and repeatability are discussed. Improvements on theCIV device design permit many measurements over a greater range ofcavity size and emitting surfaces than were possible previously. Thefindings confirm the results on compositional changes on PE voids underdischarge conditions that were found by A.M. Bruning et al. (1991)