纳米掺杂Ag(SnFe)O_2电接触合金的研究

Study of Nanocomposite Ag(Sn Fe)O_2 Contact Alloys

利用化学共沉淀、高能球磨技术及热压烧结等方法制备出纳米掺杂Ag(SnFe)O2触头合金,通过X射线衍射(XRD)、透射电镜(TEM)和冷场发射扫描电镜(FESEM)等对合金触头及其燃弧性能进行了分析。结果发现:Fe元素的加入,使SnO2纳米颗粒在550℃以下焙烧制粉和750℃以下块体烧结成型时都未明显长大,保持在20nm左右,制备的触头合金呈现纳米第二相弥散均匀分布在Ag基体中。在模拟电弧侵蚀试验中,该合金电弧阴极斑点铺展在较大区域,形成多点燃弧形貌,有效降低燃弧时间和电弧电流,分散电弧能量,使阴极斑点没有明显的液体喷溅、Ag的蒸发和第二相的分解,同时非晶的纳米第二相与Ag的润湿性更好,可进一步增加熔体粘度,提高耐电弧侵蚀性能。

Ag（SnFe）O2 electrical contacts alloys were fabricated by chemical co-precipitation, high-energy ball milling, hot pressing and sintering. The nano composites powder morphology and microstructure of contact alloys were analyzed by X-ray Diffraction （XRD）, scan electron microscopy （SEM）, transmission electron microscopy （TEM） and field emission scanning electron microscopy （FESEM）. Results show that the grain size of nanosized SnO2 doped with Fe is not obviously growth and it is about 20nm, after the composites powders are calcined at 550℃ and the samples are hot pressed and sintered or heated at 750℃. The nano-scaled second phase particles dispersed evenly in the silver matrix in the microstructure of the nano composite contacts alloys. In the experiment of arc erosion, the arc cathode spot of contact alloy spreads in a larger field and shows the shape of dotty arc burning, this can decrease the time of arc burning and arc electric current efficiently, distract the arc energy, there has not obviously splash of fused mass, vaporized of Ag and sublimated of the second phase on the nano composite contact surface, meanwhile, the nanosized second phase of non-crystalline can be more better wetted with the molten silver, this can increase its viscosity and prevent liquid silver from splatter erosion, which indicates that nano composite Ag（SnFe）O2 contacts disperse arc and has less arc erosion in the arcing process.