The work described in this paper was designed to establish the efficacy of the Module in reducing the development of corrosion damage on automobile panels and to indicate, to the extent possible, the mechanism by which protection is accomplished. The results of this study may be summarized as follows: The Module is effective in protecting galvanized steel automotive body panels, as evidenced by a shift in the potential of the exposed steel at the scribe in the negative direction. The mechanism of enhanced protection appears to be that the Module renders the zinc galvanizing (a sacrificial anode) more effective than when a Module is not connected to the system. The mechanism of protection is not that of classical, impressed current cathodic protection. This is shown by the fact that the current or voltage applied to the panel by the Module is in the form of a repetitive pulse and not a direct current that is employed in impressed current cathodic protection systems, again demonstrating a vital difference between the latter and the Module. Furthermore, the system does not contain an anode or a continuous electrolyte path between the area of damage and any connection to the Module. Unlike impressed current cathodic systems, the Module's effect is not limited to the region where a continuous electrolyte film exists between the point of application of the electrical current and the area being protected. Rather, similar to an antenna, the induced current from the Module covers the entire surface. As such, the Module is effective in reducing the rate of corrosion over the entire surface of a vehicle of complex shape. Furthermore, the frequency of the applied electrical signal is sufficiently high that the 'skin effect', whereby current flow concentrates near the surface of a conductor, may become a factor in the mechanism of protection. Activation of the zinc galvanizing by the electromagnetically-induced current occurs after an induction period. While the mechanistic details of the processes that determine the induction time are currently obscure, it is postulated that the generation of metal vacancies on the metal side of the m/bl interface result in vacancy condensation and separation of the barrier layer from the substrate metal, with the result that the barrier layer ceases to grow into the metal. However, the barrier layer continues to dissolve at the bl/s interface, with the result that the film thins and eventually ruptures, thereby activating the zinc as a sacrificial anode by exposing metallic zinc to the solution. In this manner, the Module is envisioned to enhance the efficacy of the galvanizing to protect the adjacent steel in the scribe.
Electromagnetic induction corrosion control technology (EICCT)
Korrosionsschutztechnologie mit elektromagnetischer Induktion (EICCT)
2009
20 Seiten, 17 Bilder, 4 Quellen
Aufsatz (Konferenz)
Englisch
Piston Temperature Measuring Technology Using Electromagnetic Induction
SAE Technical Papers | 2001
|Piston temperature measuring technology using electromagnetic induction
Kraftfahrwesen | 2001
|Emerald Group Publishing | 2001