Effect of electrode material on space charge behavior in epoxy resin

The effect of electrode material on the space charge behavior in epoxy resin has been investigated using the pulsed electro-acoustic (PEA) technique. Common metallic electrode materials, i.e. gold, silver and copper, were selected and sputter-coated on the specimens, and the space charge dynamics after the application of various electric fields were monitored at 293 K and 313 K. The space charge accumulation thresholds of epoxy resin with the three electrodes at these temperatures were also derived. It is found that homo space charge close to the electrodes make up the majority of the space charge in the specimens. It is pointed out that charge injection from electrodes accounts for the space charge accumulation process. Experimental results demonstrate that the electrode material has a considerable effect on the space charge behavior in epoxy resin. Furthermore, the differences in the amount of space charge accumulation and in the space charge accumulation thresholds with gold, silver, and copper electrodes are qualitatively explained by their different work functions.