A STUDY OF THE EROSION MODES OF Ag-10 CdO CONTACT MATERIAL

摘要

The erosion modes of Ag-CdO composite electrical contacts after repeated arcing were studied by means of scanning electron microscope, microprobe, and x-ray diffraction analysis. It was found that: (1) CdO particles decomposed during arcing, hence, absorbing a part of the heat, (2) a part of the cadmium recombined with oxygen and sometimes precipitated on the contact surface, (3) a part of the cadmium remained in the molten silver, it either formed a solid solution with the silver, or formed very fine oxides embedded in the silver matrix, (4) some of the oxide particles melted In the molten silver and then conglomerated into huge CdO islands, (5) heavy erosion occurred after the depletion of CdO particles.