粗晶/细晶CuCr50触头材料的电弧运动行为及其烧蚀特性

Arc Motion Behavior and Ablation Characteristics of Coarsegrained/Fine-grained CuCr50 Contact Materials

将高能球磨和等离子烧结(SPS)技术相结合制备出粗晶和细晶CuCr50电触头材料,对其成分、密度、显微硬度和电导率、放电过程中触头表面阴极斑点的分布、移动速度和触头表面侵蚀的形貌进行表征,研究了粗晶和细晶CuCr材料的电弧侵蚀特性。结果表明,细晶CuCr50触头的硬度(160.29HV)比粗晶CuCr50触头的硬度(104.15HV)高,在50 Hz工频条件下细晶触头阴极斑点的运动速度为16.9 m/s,比粗晶触头的17.78 m/s低4.9%。这表明,粗晶触头表面的阴极斑点运动到触头边缘的速度略比细晶触头的高。与粗晶触头相比,在燃弧过程中细晶触头表面产生的阴极斑点尺寸小、数量多、亮度低且更均匀;在电流幅值相同的条件下,细晶CuCr触头的电弧电压降比粗晶触头的低。电弧烧蚀后细晶CuCr触头的整体形貌平整,没有明显的大烧蚀坑和液滴喷溅。综合研究结果表明,细化第二相Cr相能显著提高CuCr50触头的整体电接触性能,细晶CuCr50触头的抗电弧烧蚀特性比粗晶触头的高。

The coarse-grained and fine-grained CuCr50 electrical contact materials were prepared by combining high-energy ball milling and spark plasma sintering(SPS)technology,and their composition,density,microhardness and conductivity,the distribution of cathode spots on the surface of the contact during discharge,the speed of movement and the morphology of contact surface erosion were characterized,and the arc erosion characteristics of coarse-grained and fine-grained CuCr materials were studied.The results show that the hardness of fine-grained CuCr50 contacts(160.29HV)is higher than that of coarse-grained CuCr50 contacts(104.15HV),and the movement speed of cathode spots of finegrained contacts is 16.9 m/s under 50 Hz power frequency conditions,which is 4.9%lower than that of coarse-grained contacts of 17.78 m/s.This suggests that the cathode spot on the surface of the coarsegrained contact moves slightly faster to the edge of the contact than the fine-grained contact.Compared with coarse-grained contacts,the cathode spots produced on the surface of the fine-grained contacts during arc burning are small in size,large in number,low in brightness and more uniform.Under the same current amplitude,the arc voltage drop of fine-grained CuCr contacts is lower than that of coarse-grained contacts.After arc ablation,the overall morphology of the fine-grained CuCr contact is flat,and there is no obvious large ablation pit and droplet splash.The comprehensive results show that the refinement of the second phase Cr phase can significantly improve the overall electrical contact performance of Cu-Cr50 contacts,and the arc ablation resistance of fine-grained CuCr50 contacts is higher than that of coarse-grained contacts.