AgWC30电接触材料的电弧行为研究

Arc Erosion Characteristics of AgWC30 Electrical Contact Material

对电弧基本行为的研究一直是电接触材料领域的研究重点,本研究以AgWC30触头为研究对象,借助高速摄像的手段,观测电触头对在不同工作条件下,电弧行为的基本特征和规律,并进行了定量测量研究。结果表明,电弧演化阶段经历起弧、稳定燃烧、迅速熄灭3个过程。起弧阶段存在多点起弧特征,并伴有明显的金属熔滴的喷溅行为,稳定燃烧阶段出现电弧的产生、长大和合并行为,最后电弧迅速熄灭。通过扫描电镜对燃弧后触头表面的形貌分析,判断触头表面存在以WC为骨架覆Ag的大量凸丘,凸丘与熔桥的产生和断裂行为有密切关系,触头分断过程中熔桥和电弧可同时存在,并存在一定的协助作用。

Arc erosion characteristics of AgWC30 electrical contact material were investigated under direct current 25 A and voltage of 20, 25, 30, 35 V. The images of breaking arc light were obtained by a high-speed camera to deduce the forming regularity of arc evolution. The results show that the arc formation processes at different voltages are similar and they go through three stages, including forming stage, steady burning and discharge quenching stage. On the other hand, the bullet-shaped convex, pore, crack and starchiness coagulum structure were observed on erosion surface of contacts by scanning electron microscopy（SEM）. The bullet-shaped convex in the break-off of liquid bridge is formed by the WC skeleton and Ag cladding. The molten bridges and the arc may co-exist and they assist each other.