| The effect of Ni doping on W powder on the sintering behavior, mechanical properties, and electrical contacting characteristics were investigated to improve the performance of electrical contact material. On the basis of these experimental results, the following conclusions were obtained. In the lower Ag content, Ni-doping seems to be considerably more effective on densification of the W-Ag-Co system, than dopent Co, but both dopent, Ni, Co, were less effective in the higher Ag content. In the sintering of Ni doped W-Ag-Co system, the volume expansion appeared as well as in pure W-Ag-Co system. By the model approach and X-ray diffraction analysis, it was identified that the formation rate of intermetallic compound, Co_7W_6, was reduced by Ni doping, but there was no difference between Ni doped W-Ag-Co system and pure W-Ag-Co system in chemical composition and microstructure after sintering for 3hrs, and it was observed that dopent Ni accelated the densification of W-Ag-Co system. Hardness was increased and contact erosion was decreased by Ni doping of W powder in W-Ag-Co base contact material. Therefore Ni doped W-Ag-Co base sintered alloys are recommended as a electrical contact material that requires the frequent make and break like a vibrator. |
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