Arc Erosion/Welding Behavior of Al₂O₃-Doped Cu-W Alloy Formed by Vacuum Sintering

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.