Effects of Dissimilar Metal Coupling, Potential Distribution, and Temper Condition on Galvanic Corrosion of 5086 Aluminum Alloy in Synthetic Seawater
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Authors
Perkins, Jeff
Locke, J.S.
Graham, K.J.
Subjects
galvanic corrosion
5086 aluminum alloy
5086 aluminum alloy
Advisors
Date of Issue
1978-01
Date
January 1978
Publisher
Monterey, California. Naval Postgraduate School
Language
Abstract
The galvanic corrosion behavior of 5086 aluminum alloy in three tempers {Hll6,
Hll7, H32) when coupled with more noble metals {1040 steel, naval brass, and
Ti-150A titanium) and immersed in aerated synthetic seawater, was studied.
Galvanic current density measurements, potentiodynamic polarization
determinations, and optical and electron microscopic observations were made.
Galvanic corrosion of 5086 aluminum was found to be independent of temper and to decrease in the order (of coupled metals) Ti > naval brass> 1040 steel. The effect of dissimilar metal coupling decreases with time due to the formation of corrosion or product deposits on both anodic and cathodic surfaces. Coverage of the surface of the aluminum (anodic) member of
couples with corrosion products tends to promote the operation of local
corrosion modes. Correlations have been made between corrosion product distribution and the distribution of dissolution attack by microscopic means, and the relation of these features to potential distribution is discussed.
Type
Technical Report
Description
Series/Report No
Department
Mechanical and Aerospace Engineering (MAE)
Organization
Naval Postgraduate School
Identifiers
NPS Report Number
NPS-69PS-78-001
Sponsors
Naval Research, Metallurgy Program Office, Code 471
Funder
N00014-77-WR-70215, NR-036-120
Format
63 p.
Citation
Distribution Statement
Approved for public release; distribution is unlimited.
Rights
This publication is a work of the U.S. Government as defined in Title 17, United States Code, Section 101. Copyright protection is not available for this work in the United States.