真空烧结制备电触头Cu-W/Al2O3合金组织和侵蚀性能分析

Arc Erosion/Welding Behavior of AlO-Doped Cu-W Alloy Formed by Vacuum Sintering

选择真空烧结方法制得组成为Cu-33.6W/Al2O3与Cu-26.8W/Al2O3的两种合金,并对电导率、组织致密度以及表面硬度进行分析,表征了经过电弧侵蚀得到的微观形貌及其熔焊性能。研究结果表明:以真空烧结方式制得的Cu-W/Al2O3触头达到了高于97%的致密度,随着W含量的提高,试样电阻率减小,硬度增加。在铜基体中出现了弥散态的Al2O3颗粒,实现弥散增强效果,显著提升合金耐高温能力。对阳极与阴极触头进行每次电接触测试时都发生了质量减小。采用DC(30 V,30 A)参数对触头阳极与阴极进行侵蚀,形成了长条状、液滴形以及凹凸变化的微观侵蚀形貌。施加10 A电流时,在最初测试阶段形成了大幅波动的熔焊力,随着合金内的W比例从26.8%提高到33.6%的过程中,材料获得了更强的抗熔焊性能。

The bulk Al2O3-doped Cu-W alloy,an advanced contact material with compactness over 97%for electrodes of vacuum circuit breaker,were synthesized with Cu-0.4%Al,Cu2O,W and Cr powders and formed by vacuum sintering.The influence of the W-content and Al2O3-doping on the tribological properties,arc-eroded microstructures and arc erosion resistance was investigated with SEM,TEM and EDS.The results show that the W-content and Al2O3-doping had a major impact.To be specific,the well-dispersed Al2O3-particles significantly enhanced the mechanical strengthen and high temperature resistance of the Cu-base;a higher W-content(an increase from 26.8 wt%to 33.6 wt%)resulted in a lower resistivity,a stronger hardness and a greater resistance against fussing-welding.An arc discharge at 30 V and 30 A brought about fluctuating welding-force,slight mass-loss,and observable formation of micro/nano-structures,including the spherical droplets,ling stripes and coral-like clusters on the arc-eroded surfaces.