Erosion and Transfer in Electrical Contacts Measured Using the Thin Layer Activation Technique

The application of an ion beam activation technique to erosion studies in electrical contacts is demonstrated. The technique, which is based upon the labeling of a thin layer of surface atoms by high energy ion beam activation, is sensitive to both material loss from the activated layer and transfer to other components. As only a thin layer is activated the induced activity levels are low and the samples require only elementary radiological handling precautions. The information that can be obtained with the technique is demonstrated with the use of a readily available automobile contact rig incorporating tungsten contacts. Preliminary estimates of the erosion conditions are made, and the technique is then tailored to optimize experimental measurements. A typical measurement of material transfer between the two electrode faces was 50 ± 3 µg per 2 h of operation. An attempt to modify the properties of electrodes and hence their erosion rates by the ion implantation of silver ions is also reported.