纳米AgSnO_2触头合金的电弧侵蚀特性

采用化学共沉淀、高能球磨、常压烧结等方法制备了纳米AgSnO_2触头合金,对合金的密度、硬度、电阻率等物理性能及其组织结构进行了分析研究,利用高速摄像机对纳米AgSnO_2和商用AgSnO_2In2O3触头合金的燃弧过程进行了跟踪拍摄,对比研究了电弧侵蚀前后合金的表面形貌。结果表明,纳米AgSnO_2触头合金内部的纳米氧化物颗粒均匀弥散地分布于银基体内。与商用AgSnO_2In2O3合金相比,纳米AgSnO_2触头合金具有较高的硬度及电阻率,而密度偏低。在燃弧试验过程中,纳米AgSnO_2触头合金电弧等离子云颜色浅、体积大,电弧弧根对应的阴极斑点数量多、区域大,具有较强的分散电弧能力以及优良的耐电弧侵蚀性能。燃弧后,合金表面烧蚀轻微,电弧烧蚀率明显小于AgSnO_2In2O3合金。

Arc Erosion Characteristic of Nano AgSnO2 Contact Alloys

The nano Ag-SnO2 electrical contact alloys were prepared by chemical coprecipitation, high-energy ball milling and general sintering technique. Its physical properties including density, hardness, and resistivity were also investigated. And then, the arc discharging process and microstructures of nano AgSnO2 and AgSnO2In2O3 contact alloy were observed by high speed camera and scanning electron microscopy (SEM). Results show that the nanosized SnO2 particles are uniformly dispersed within the Ag matrix of nano Ag-SnO2 electrical contact alloys. Comparing with AgSnO2In2O3 contact alloy, nano Ag-SnO2 electrical contact alloys show the higher hardness and resistivity, but the lower density. At the same time, nano AgSnO2 contact alloy exhibits bigger volume of the plasma clouds and dimmer arc emitting spectrum. It also has more cathode spots on arc roots and has a larger motion region on the contact surfaces. As a result, the arc is dispersive and the heat stream input of cathode spots is decreased, demonstrating a better performance of arc erosion resistance. After arc discharging, the melting of nano AgSnO2 contact is slight and the arc erosion rate is remarkably smaller than AgSnO2In2O3 contact alloy.