Effect of Ag-Ni and Ni Coating Materials on Fretting Wear Properties of Copper Electrical Contact
Copper is often used in high and low voltage switch contacts because of its good electrical conductivity.Under actual working conditions,the electrical contact will be subjected to external vibration,and its contact surface will be worn,which will reduce the electrical contact performance.Two kinds of electric contact materials,Ag-Ni and Ni,were electro-plated on the surface of red copper,and the electric contact fretting wear tests were carried out under different loads on the electric contact fretting wear testing machine.The change curves of contact resistance and friction coefficient of the two kinds of coating materials were analyzed.The results show that with the increase of load,the friction coefficient of different coating materials decreases.When the load is constant,the average friction coefficient of electroplated Ag-Ni sample is low-er than that of uncoated and electroplated Ni samples.The contact resistance of different coating materials decreases with increasing load.After 4 000 cycles,compared with uncoated and electroplated Ni samples,the electroplated Ag-Ni sample has the lowest average contact resistance,indicating that electroplated Ag-Ni improves the conductivity of copper to a cer-tain extent.The electroplated Ni sample exhibits superior wear resistance due to the higher surface hardness,which has the lowest wear volume compared to uncoated and electroplated Ag-Ni samples.The analysis of wear mechanism shows that,in the process of micromotion,the generation and elimination of oxidized wear debris will lead to sharp fluctuations in contact resistance,and the contact resistance is positively correlated with the proportion of oxide area on the surface of the wear mark.The wear mechanism of two kinds of coating materials is mainly adhesive wear.
electrical contactfretting wearcontact resistancecopper based electrical contact materialselectroplating
NETL
NSTL
万方数据
