Effect of Fretting on the Contact Resistance of Aluminium with Different Contact Materials

The effect of fretting on the contact resistance of aluminium wire (EC grade) and different plating materials (Ag, Cd, Ni, Sn, Zn) has been studied. The fretting tests were conducted with simulated connector configurations using a differential thermal expansion fixture to produce fretting damage. In addition, the waveforms of the contact voltage, scanning electron microscopy (SEM), and X-ray fluorescence analysis were used to study thc processes involved. The results show that the contact resistance of all combinations of aluminium-contact materials increases very rapidly after a given number of fretting cycles. The effects of fretting are reduced to some extent by applying higher electrical and contact loads. The waveforms of the contact voltage across the couples are severely distorted by the fretting action. The SEM and X-ray fluorescence analyses showed that the contact zones are severely damaged and that substantial transfer of material occurred as a result of the fretting action.