Surface films on precious-metal contacts

Angus, H. C.

doi:10.1088/0508-3443/13/2/303

Cited by 24 publications

(17 citation statements)

References 2 publications

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“…Tougaard analysis on the spectra suggests the carbon-containing layer has a thickness of 4 -6 nm. With TOF-SIMS, Au x (CN) y , Au x I y , SO 3 Ϫ , and SO 4 Ϫ were observed before exposure to ozone. Following exposure, however, the Au x (CN) y and Au x I y concentrations were reduced (Au x I y signal was absent͒, while SO 3 Ϫ and SO 4 Ϫ were concentrations were increased.…”

Section: Resultsmentioning

confidence: 99%

“…Previous large-area contact studies in air have demonstrated how a prepared contact surface can deteriorate with time, and have also shown that a nonmetallic contamination film is typically present on metal contact surfaces which produces a resistance in series with the constriction resistance. 4 In fact, this nonmetallic ''contamination layer,'' together with other properties of real surfaces that are difficult to quantify, often prevent direct comparison of theoretically predicted behavior with that experimentally observed. 5 For example, a careful study of two microscopically rough gold surfaces in air showed that water and hydrocarbons completely dominate the gold-gold contact properties at low force levels.…”

Section: Introductionmentioning

confidence: 99%

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A single asperity study of Au/Au electrical contacts

Tringe

Uhlman

Oliver

et al. 2003

Journal of Applied Physics

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Plasma polymerization and deposition of linear, cyclic and aromatic fluorocarbons on (100)-oriented single crystal silicon substrates Interfacial force microscopy ͑IFM͒ is used to measure the electrical contact properties of electroplated gold thin films of the type used in microelectromechanical system relays. Force and current levels consistent with those present in metal-metal contact switches are examined in an atmospheric-pressure, dry-nitrogen ambient at room temperature, and the nature of a nonmetallic contamination layer which limits contact resistance and lifetime is explicitly examined mechanically, electrically and chemically. The electrical and mechanical properties of the contamination layer on the gold substrate are observed by IFM both before and after being exposed to ozone for an extended period of time. The contamination film is characterized by x-ray photoelectron spectroscopy and time-of-flight secondary ion mass spectrometry, and found to consist mostly of hydrocarbons; the film remains relatively stable in both composition and thickness following ozonation. However, some subtle chemical changes in the contamination layer induced by the ozonation process are found to profoundly affect the electrical properties of the gold-gold contact, reducing the resistance by more than 3 orders of magnitude and considerably reducing variability in the contact resistance between contact events. These results clearly demonstrate the critical role both positive and negative of the latent contamination present on the contact surfaces.

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Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

A single asperity study of Au/Au electrical contacts

Tringe

Uhlman

Oliver

et al. 2003

Journal of Applied Physics

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“…Die Schichtdicke aller verwendeten Kugeln wurde zur besseren Vergleichbarkeit auf 400 nm festgelegt. Diejenigen Beschichtungssequenzen, die auf Palladium auf einer Goldschicht basieren, wiesen eine längere Haltbarkeit auf, [16] ). Es ist zu beachten, dass Referenzversuche bewiesen haben, dass weder die verwendeten Zwischenschichten selbst zur Suzuki-Kopplung beiträgt (Hintergrundinformationen Tabelle S1), noch ist irgendein mögliches abgeschliffenes Material katalytisch aktiv.…”

Section: Ergebnisse Und Diskussionunclassified

Vom inerten zum katalytisch aktiven Mahlmedium: Galvanostatische Beschichtung für direkte Mechanokatalyse

et al. 2022

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Die inerten Mahlkugeln, die üblicherweise bei mechanochemischen Reaktionen verwendet werden, wurden mit Pd beschichtet und als Katalysator in der direkten mechanokatalytischen Suzuki‐Reaktion eingesetzt. Mit hohen Ausbeuten (>80 %) können die Mahlkugeln in Abwesenheit von Lösungsmitteln, Liganden, Katalysatormolekülen und ‐pulvern mehrfach recycelt werden, wobei nur 0,8 mg Pd pro beschichteter Mahlkugel benötigt werden. Neben der Beschichtungsreihenfolge, wurde zudem das Trägermaterial und die Schichtdicke untersucht, um eine hohe Katalysatorretention, einen geringen Abrieb und einen hohen Umsatz zu erzielen. Der Ansatz wurde auf die Beschichtung von Mahlbechern übertragen, um das Zusammenspiel von katalytisch verfügbarer Oberfläche und mechanischer Energieeinwirkung bei der direkten Mechanokatalyse aufzuzeigen.

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“…that crack growth, but not crack initiation, is delayed in the absence of an atmosphere. Whether or not this is in contradiction with the conclusion reached by Broom and Nicholson (1961), that crack initiation in age-hardened aluminium is delayed most of all, depends upon how far the initiation and early crack growth can be considered as separate stages. The early stages of growth may take place by repetitions of the same changes which lead to the production of the first small crack, in which case a change in environment would effect equally the initiation and early growth.…”

Section: Discussionmentioning

confidence: 77%