Formation Mechanism of Dark Bridge between Contacts with Very Slow Opening Speed

Hiroyuki ISHIDA  Shosuke SUZUKI  Hideaki SONE  Hiroshi INOUE  Masanari TANIGUCHI  Tasuku TAKAGI  

IEICE TRANSACTIONS on Electronics   Vol.E89-C    No.8    pp.1136-1140
Publication Date: 2006/08/01
Online ISSN: 1745-1353
DOI: 10.1093/ietele/e89-c.8.1136
Print ISSN: 0916-8516
Type of Manuscript: Special Section PAPER (Special Section on Recent Development of Electromechanical Devices (Selected Papers from IS-EMD2005))
Category: Contact Phenomena
dark bridge,  bridge shape,  thermal expansion,  

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The mechanism of dark bridge formed with very slow contact separating speed was empirically shown with some discussions from the experimental results which the authors have obtained by using the cantilever system for controlling contact gap. By analyzing the obtained results, we will assume some concept of formation mechanism of dark bridge. Since the thermal effect is inevitable in the bridge formation, this will be inferred from two points; one is the a-spot change at initial state of bridge forming, and another one is the thermal expansion due to bridge current that affects the shape of bridge. This paper will show from these two points the conceptual bridge formation mechanism in case of non-melting state of contact bridge which is called here dark bridge.