Ag/SnO2电接触材料的制备及其燃弧特性研究

Preparation and Arcing Characteristics of Ag/SnO2 Electrical Contacts

以Ag粉和自制SnO2为原料,采用机械合金化和热挤压拉拔工艺制备Ag/SnO2电接触材料。采用冷压焊工艺设备制备了Ag/SnO2铆钉元件。采用X射线衍射仪(XRD)对Ag粉、自制SnO2及Ag/SnO2复合粉体进行物相分析;采用扫描电子显微镜(SEM)对电寿命测试前后Ag/SnO2铆钉元件的表面形貌进行了表征。并考察了不同电气参数对Ag/SnO2铆钉元件的燃弧特性、电弧侵蚀形貌、质量损失及其失效退化模式等特性研究。结果表明:Ag/SnO2电接触材料在电弧作用下相比于纯Ag表现出更高的燃弧时间和燃弧能量,平均闭合与断开燃弧时间分别为51.78和25.86 ms,比纯Ag多出4.87和2.78 ms;同理,平均闭合、断开燃弧能量分别为988.14和493.85 mJ,比纯Ag高出104.93和58.76mJ;随着循环操作次数的增加,Ag/SnO2电接触材料的总质量损失为负值,其失效退化模式主要表现为液滴飞溅与SnO2颗粒上浮。

Using Ag powder and nano-SnO2 as raw materials,Ag/SnO2 electrical contact materials and its rivets were prepared by mechanical alloying and hot extrusion and cold press-welding process.The phase composition of the commercial Ag powder,as-prepared SnO2 and Ag/SnO2 composite powders was analyzed by X-ray diffractometry(XRD).The surface morphology and arcing characteristics and mass loss of the rivets before and after the electrical life test were characterized by scanning electron microscopy(SEM).The effects of different process parameters(working current and cycle number)on the arcing characteristics,arc eroded morphology,mass loss and degradation mode of Ag/SnO2 contacts were analyzed and compared.The results show that compared with pure Ag,Ag/SnO2 electrical contacts have higher arcing time and arcing energy under arcing,and the average arcing time of making-arc and breaking-arc is 51.78 and 25.86 ms,which is 4.87 and 2.78 ms higher than that of pure silver,respectively;the average arcing energies of making-arc and breaking-arc are 988.14 and 493.85 mJ,which are 104.93 and 58.76 mJ higher than those of pure silver,respectively.As the number of cycle operations increases,the total mass loss of the Ag/SnO2 electrical contacts is negative,and its main failure degradation modes of droplet splatter and SnO2 particles floating are manifested.