Effect of Micron-scale and Nanoscale Boron Nitride Fillers on Arc Ablation Resistance of Polytetrafluoroethylene

During the breaking process of high voltage circuit breaker (HVCB), the arcs generated between the contacts may cause severe ablation of the nozzle, shortening the life of HVCB. Therefore, it is necessary to study the nozzle material with better ablation resistance. Polytetrafluoroethylene (PTFE)/boron nitride (BN) composite materials are commonly used in the industry to prepare nozzles. The particle size of BN can affect the ablation resistance of PTFE/BN composites, but the law is still unclear. In this paper, several kinds of PTFE composite samples doped with different nanoscale and micron-scale BN were prepared to study the effect of BN size on ablation resistance. The experimental results show that micron-scale BN fillers are more effective for improving the ablation resistance. With the increase of micron-scale BN particle size, the arc ablation resistance becomes better first and then worsens. The results are discussed and explained from the perspective of thermal transport and spectral reflectance characteristics.