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Mechanically-induced degradation of metallic sliding electrical contacts in silicone fluid at room temperature

Electrical Contacts, Proceedings of the Annual Holm Conference on Electrical Contacts

Dugger, Michael T.; Groysman, D.; Celina, Mathias C.; Alam, Todd M.; Argibay, Nicolas A.; Nation, Brendan L.; Prasad, Somuri V.

The degradation in electrical contact resistance of a contact pair sliding while submerged in silicone fluid has been investigated. While the contamination of electrical contacts by silicone vapors or migrating species at elevated temperature due to decomposition in electric arcs is well known, the present degradation mechanism appears to arise from chemical reactions in the silicone fluid at room temperature, catalyzed by the presence of the freshly-abraded metal surface. As a result of these reactions, a deposit containing Si, C and O forms in the vicinity of mechanical contact. The specific contact metals present and the availability of dissolved oxygen in the fluid have a dramatic influence on the quantity of reaction product formed. The chemistry of the deposit, proposed formation mechanisms, the impact on electrical contact resistance and mitigation strategies are discussed.

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TYPE Conference Poster YEAR 2015
ScopusOSTIDOI

He implantation for improved tribological performance in Au electrical contacts

Journal of Materials Science

Mogonye, Jon-Erik M.; Hattar, K.; Kotula, Paul G.; Scharf, Thomas W.; Prasad, Somuri V.

This paper describes the role of He ion implantation on the friction, wear, electrical contact resistance (ECR), and near surface microstructure of Au films. The films were deposited by e-beam evaporation and implanted with He under two different conditions. Electrical contact resistance and friction data were collected simultaneously, while sliding a Au-Cu alloy pin on He ion implanted Au films. Results showed that friction coefficients were reduced from ~1.5 to ~0.5 and specific wear rates from ~4 × 10−3 to ~1 ×10−4 mm3/N m (both versus un-implanted samples) without a significant change in sliding ECR (~16 mΩ) as a result of He ion beam implantation. Subsurface microstructural changes due to tribological stress and the passing of current were analyzed using site-specific cross-sectional TEM. The implantation of He by itself did not induce changes to the grain size or crystallographic texture of e-beam Au. However, frictional contact during ECR testing of low energy He implanted films resulted in the formation of stable equiaxed nanocrystalline grains and the growth and redistribution of cavities beneath the wear surface. Plastic deformation as evidenced by transfer of Au to the pin during frictional contact was significantly reduced as a result of implantation. This was hypothesized to be a result of Orowan-like hardening due to He implantation.

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TYPE Journal Article YEAR 2015
ScopusOSTIDOI
Results 26–50 of 122
Results 26–50 of 122