Tracking and erosion of HTV silicone rubbers of different thickness

Tracking and erosion behaviors of high temperature vulcanized (HTV)-silicon e rubber (SIR) of 0.5 to 6.0 mm thicknesses were investigated in order to o btain the optimum thickness for enhancing tracking and erosion resistance u nder various leakage current levels. Under low leakage current, thinner sam ples showed a higher tracking and erosion resistance, while under medium an d high leakage current, thicker samples showed better resistance to these b ehaviors, The optimum thickness to prolong the time to tracking and erosion failure appeared in the range of 1.0 to 3.0 min thickness. The content of an initial low molecular weight (LMW) silicone fluid was shown to be closel y related to the development of leakage current and high temperature therma l spots. The results indicate that the sample thickness is crucial to the a bility of HTV-SIR to withstand a large number of high temperature thermal s pots under condition of high level leakage current.