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

Volume

11

Issue

1

fYear

1988

fDate

3/1/1988 12:00:00 AM

Firstpage

68

Lastpage

73

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;

fLanguage

English

Journal_Title

Components, Hybrids, and Manufacturing Technology, IEEE Transactions on

Publisher

ieee

ISSN

0148-6411

Type

jour

DOI

10.1109/33.2964

Filename

2964