The initiation of high current density switching in electrically conductive polymer composite materials

In this paper, the idea that high power switching in conductor-filled polymer composite materials is triggered by the injection of a high energy density at the electrical contact interfaces is tested. A simple theoretical model for the electrical contact interface is developed and used to predict that the time required for switch initiation should be inversely proportional to the square of the product of average initial current and contact resistance. This scaling prediction is tested by means of switching experiments where the switch initiation time is monitored as a function of average initial current level and contact resistance. It is found that the experimental data are consistent with the theory over a variation of more than three orders of magnitude in both initial current level and contact resistance. In addition, it is determined that the data are consistent with the interpretation that polymer ablation is the physical event which triggers switching. (C) 1998 American Institute of Physics.