Investigation on the response of ZnO/SiR composites under impulse voltage

The polymer materials doped with ZnO microvaristors show similar nonlinear conductivity characteristics to the ZnO varistors, which is promising to be used in the insulation of power apparatus as function materials. It is possible that the power equipment would suffer the transient process during the operation, and the behavior of ZnO/SiR composites under such conditions is worth investigating. This study prepared ZnO/SiR samples with different filler volumes for the impulse voltage test. SEM and digital source meter were used to characterize the microscopic surface morphology and DC response of the composites, respectively. With the increase of applied impulse voltage, the transition from capacitive to nonlinear resistive response of is obtained. While the response is just capacitive at low voltage, there is obviously a nonlinear resistive component seen in the time development of
$I$
(t) at higher voltages.