The partial discharge activity during propagation of electrical treeing in epoxy resin is described. The electrical trees grew in needle-plane samples without and with an internal barrier up to the final breakdown. The simultaneous taken tree growth and discharge activity show a correlation between the propagation state of the tree and the thereby measured PD. Especially the changes in the tree...

The use of unconventional machining techniques in shaping metal matrix composites (MMCs) has generated considerable interest as the manufacturing of complicated die contours. Metal matrix composites are advanced materials having high specific strength, good wear resistance, and high thermal expansion coefficient. Electrical discharge machining is a best process to make complicated shapes on the...