Degradation of Electrical Contacts Caused by Oscillatory Micromotion Between the Contact Members

The influence of oscillatory movement on the contact resistance is discussed on the basis of experiments with contacts in a crossed rod configuration, the contact members being Al-Al and Cu-Cu. Measurements were carried out for movements of amplitudes within the range 0.4-18 µm and mechanical loads between 20-170 N at frequencies 10-100 cycles/h. The experimental results show that micromotion under certain conditions causes rapid and extensive degradation. For Al contacts with load 20 N, the resistance increases to 50 times the initial value after 200 cycles.