THE USE OF ELECTROCHEMICAL IMPEDANCE SPECTROSCOPY TO PREDICT THE CORROSION OF ALUMINUM-LITHIUM ALLOYS IN MARINE ENVIRONMENTS

Authors
  1. Lenard, D.R.
  2. Moores, J.G.
  3. Roberge, P.R.
  4. Halliop, E.
Corporate Authors
Defence Research Establishment Pacific, Victoria BC (CAN);Royal Military Coll of Canada, Kingston ONT (CAN)
Abstract
In order to acquire some experience with the behaviour of aluminium-lithium alloys in the marine environment, the Defence Research Establishment Pacific compared panels made from AA 2090 and 8090 sheet with the conventional alloys AA 7075 and 2024, respectively, in several tests involving long term exposure to sea water fog and full or partial immersion in sea water. The results of these tests were then compared with the results of a new technique, developed by the Royal Military College of Canada for the analysis of electromechanical impedance measurements, that was performed on these alloys in simulated sea water. The long term exposure tests indicated that corrosion problems, could occur with aluminum-lithium alloys in the marine environment. The 8090 alloy was found to suffer from severe localized attack, including intergranular cracking, along edges that were immersed in sea water. The 2090 alloy, however, appeared to offer some advantages over its 7075-T6 counterpart, as it was more resistant to corrosion at its edges, even though it suffered as much or more corrosion on the rolled surfaces.
Keywords
ELECTROCHEMICAL IMPEDANCE SPECTROSCOPY;Al-Li ALLOYS;MARINE ENVIRONMENT
Report Number
DREP-TM-92-43 — Technical Memorandum
Date of publication
01 Dec 1991
Number of Pages
46
DSTKIM No
94-02956
CANDIS No
130853
Format(s):
Hardcopy;Originator's fiche received by DSIS

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