基于CO_2连续激光器模拟的氮化物填充聚四氟乙烯复合材料耐烧蚀性能

通过在聚四氟乙烯(PTFE)基体中添加不同比例微米、纳米尺度氮化硼(BN)或氮化铝(AlN),以提高高压断路器PTFE喷口复合材料的耐电弧烧蚀性能。利用CO2连续激光器烧蚀PTFE喷口材料来模拟电弧烧蚀过程,分析了光反射率、热导率以及相对介电常数对烧蚀量的影响。通过比较复合材料烧蚀量大小和数值分析结果可知,材料热学参数(热导率和热扩散系数)对烧蚀量起主要作用,BN/PTFE复合材料的耐烧蚀能力优于AlN/PTFE复合材料,10.0%BN/PTFE复合材料的热导率可以达到0.46W/(m·K),比纯PTFE的提高了92%,相应烧蚀过程中的质量损失为21.8mg,比3.0%AlN/PTFE复合材料的质量损失降低了47%,有效提高了喷口复合材料的耐烧蚀能力。

Ablation resistance property of nitride filled polytetrafluoroethylene composites based on CO2 continuous laser simulation

In order to improve the arc-resistance ablation property of polytetrafluoroethylene (PTFE) nozzle composites of high voltage circuit breaker, micro or nano size boron nitride (BN) or aluminium nitride (AlN) with different ratios were dispersed into PFTE matrix. CO₂ continuous laser was used for ablating PTFE nozzle material to simulate electric arc ablation process. The effects of light reflectance, thermal conductivity and relative dielectric constants on ablation amount were analyzed. By comparing ablation amount of composites and numerical analytical results, the key factors affecting ablation amount are thermal parameters of materials (thermal conductivity and thermal diffusion coefficient). BN/PTFE composites have higher ablation resistance property compared with AlN/PTFE composites. The thermal conductivity of 10.0% BN/PTFE composites is up to 0.46 W/(m·K) which is 92% higher than that of pure PTFE. The mass loss of 10.0% BN/PTFE composits in ablation process is 21.8 mg, which is 47% less than that of 3.0% AlN/PTFE composites. The ablation resistance property of nozzle composites is effectively improved.