Accession Number:

AD0261743

Title:

STUDY OF EFFECTS AND CONTROL OF SURFACE CONTAMINANTS ON ELECTRICAL MATERIALS

Descriptive Note:

Corporate Author:

STANFORD RESEARCH INST MENLO PARK CALIF

Personal Author(s):

Report Date:

1961-06-10

Pagination or Media Count:

1.0

Abstract:

The cause of objectionable contact resistance was studied in relay contacts used in millivoltmicroampere switching. Organic deposits form spontaneously on noble metal contact surfaces. Deposits formed over a period of weeks or months from a number of pure organic compounds and, as well, from rosin flux and from Teflon and Kel-F. Insulating deposits were detected with a fine wire probe and with the electron microscope. Frictional polymer, formed when metals are rubbed together in an organic environment developed from outgassing rosin flux and Teflon and Kel-F. Four metals were found to generate decreasing amounts of frictional polymer in the order Pd, Au-alloy, Au, Ag, with the following approximate activity ratios 100, 10, 2, 0.1. A non-destructive relay test for contact contamination was developed based on monitoring at dry circuit load levels and a contact resistance sensitivity of 0.1 ohm. The relays were put through a 7step schedule in which time, temperature, and relay cycling were varied. Author

Subject Categories:

Distribution Statement:

APPROVED FOR PUBLIC RELEASE