新型Ag-5%C电接触材料的制备及其电弧磨损特性的研究

Fabrication of a Newly Developed Ag-5%C Electrical Contact Material and Its Arc Erosion Characteristics

采用将高能球磨、还原剂液相喷雾化学包覆及粉末冶金相结合配以适量碳纳米管做为纤维增强体的工艺 ,制备出新型的Ag 5 %C(质量分数 )电接触材料。该材料具有优异的烧结致密性 ,烧结复压密度可达理论密度的 99.9%,而传统机械混粉工艺及国外发展的烧结挤压工艺同类材料仅能达到 97.0 %～ 98.4%;其硬度达到 64 5MPa ,大大超过同类触头 ;该新型材料由于C在基体中的均匀分布以及高烧结致密性 ,具有很好的导电性能 ,其电导率达到了 3 8 0m·Ω- 1 ·mm- 2 ,远超机械混粉工艺而接近烧结挤压工艺。经由ASTM触头材料试验机进行电磨损分断对比试验 ,发现与常规机械混粉同类触头相比 ,该材料同等条件下电弧磨损量小得多 ,且具有优异的电弧磨损特性 ,其电弧磨损量随分断次数呈指数小于 1的指数函数规律上升 ,即到分断后期其材料损耗量趋于稳定 ,有效抑制了触头分断电涡流磨损现象 ,这种优异的电弧磨损特性对于提高其材料耐电弧磨损性能具有重要意义。

Applying the technique of high energy ball milling in conjunction with reducer liquid spraying chemical coating and powder metallurgy, a newly developed Ag 5%C (by weight including partial carbon nanotubes) electrical contact material was fabricated. Compared with those convenient counterparts made from traditional blending and extrsion, the new material has superior physical and mechanical properties. Its density ratio, electriconductivity and hardness reach to 99.9%, 38.0 m·Ω -1 ·mm -2 and 645 MPa, respectively. The experiments for arc erosion behavior of the prepared contacts by breaking arcs were done by using an ASTM contact material automatic measuring device. The experimental results indicate that the weight loss of the newly developed AgC5 material by the same arc breaking is less than that of the convenient blending counterpart. It is found that the newly developed material has excellent arc erosion characteristics. The newly developed Ag/C may be substitute for those counterparts made from extrusion or blending as a new electrical contact material.