Title :
Metallurgical study of Ag-Cd and Ag-CdO alloy electrical contacts
Author :
Furtado, Heloisa Cunha ; Da Silveira, Vera Lucia Antunes
Author_Institution :
Centro de Pesquises de Energia Eletrica, Rio de Janeiro, Brazil
fDate :
3/1/1988 12:00:00 AM
Abstract :
Ag-Cd and Ag-CdO contacts, made both by sintering and postoxidation, were evaluated as to their durability by inductive and capacitive overcurrent tests according to the IEC 328 and NBR 6269 standards. Materials transfer during electric tests were monitored at 10000, 20000, 30000, and 40000 switching operations by scanning electron microscopy (SEM), energy-dispersive X-ray analysis, and chemical analysis. Better performance with regard to erosion was found for Ag-CdO postoxidized contacts, compared with sintered ones. Structural changes on the surface of Ag-Cd and Ag-CdO contacts were studied by SEM. The surface of Ag-Cd contacts changed rather uniformly, while Ag-CdO contacts developed considerable inhomogeneity. Sintered and postoxidized contacts also have also different structures. Sintered Ag-CdO contacts show a matrix with pulverized droplets while postoxidized Ag-CdO show very little change
Keywords :
X-ray chemical analysis; cadmium alloys; cadmium compounds; electrical contacts; materials testing; scanning electron microscope examination of materials; silver alloys; 40000 switching operations; Ag-Cd contacts; Ag-CdO alloy electrical contacts; Ag-CdO contacts; EDAX; IEC 328 standards; NBR 6269 standards; SEM; capacitive overcurrent tests; chemical analysis; durability; electric tests; energy-dispersive X-ray analysis; erosion; inductive overcurrent tests; material transfer; matrix with pulverized droplets; metallurgical study; postoxidation; postoxidized contacts; scanning electron microscopy; sintered contacts; sintering; structures; Circuit testing; Contacts; Fixtures; IEC standards; Oxidation; Scanning electron microscopy; Switches; Switching circuits; Thermal conductivity; Thermal stresses;
Journal_Title :
Components, Hybrids, and Manufacturing Technology, IEEE Transactions on
