Novel metal contact material for low voltage circuit breakers application

This article shows the evaluation of a new Cu-base metal contacts applied to low voltage circuit breakers. The general performance of the developed material was similar to the one obtained with the common Ag-base metal contacts used in this type of devices and conditions. The developed Cu-base contact material was tested under UL 489 standard conditions. The temperature rise test shows at difference around 9 degrees C between both materials at steady state conditions; endurance and short circuit test don't show evident differences between both type of contacts. SEM images exhibit how is the homogenous dispersion of alloying elements in the Cu compound of the contact, and with a chemical mapping analysis is possible to elucidate the no presence of oxide compounds in the surface and internally in the contact material after the tests. The homogenous distribution of the alloying elements in the conductive metal compound of the contact, allows a uniform distribution of properties, reducing the risk of the oxide layer formation.