ASTM D2803-93

Designation: D 2803 – 93
AMERICAN SOCIETY FOR TESTING AND MATERIALS
100 Barr Harbor Dr., West Conshohocken, PA 19428
Reprinted from the Annual Book of ASTM Standards. Copyright ASTM
Standard Guide for Testing
Filiform Corrosion Resistance of Organic Coatings on
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Metal
This standard is issued under the fixed designation D 2803; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A
superscript epsilon (e) indicates an editorial change since the last revision or reapproval.
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1. Scope by Means of Aqueous Solutions
2.2 International Standard:
1.1 This guide covers three procedures for determining the
ISO 4623 Paint and Varnishes—Filiform Corrosion Test on
susceptibility of organic-coated metal substrates to formation
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Steel
of filiform corrosion.
1.2 This guide is limited to the determination of whether
3. Terminology
filiform corrosion will occur between the organic coating and
3.1 Definitions:
substrate.
3.1.1 filiform corrosion—a special type of corrosion that
1.3 This standard does not purport to address all of the
occurs under coatings on metal substrates that is characterized
safety problems, if any, associated with its use. It is the
by a definite threadlike structure and directional growth.
responsibility of the user of this standard to establish appro-
3.1.1.1 Discussion—Filiform corrosion usually occurs be-
priate safety and health practices and determine the applica-
tween 70 and 95°F (20 and 35°C), with a corresponding
bility of regulatory limitations prior to use.
relative humidity range of 60 to 95 %; above 95 % humidity,
2. Referenced Documents blistering rather than filiform corrosion may occur.
2.1 ASTM Standards:
4. Summary of Method
B 117 Practice for Operating Salt Spray (Fog) Testing
2 4.1 Coated metal specimens are scribed and placed in a
Apparatus
corrosive atmosphere to initiate corrosion. The specimens are
D 609 Practice for Preparation of Cold-Rolled Steel Panels
then exposed to controlled temperature and humidity condi-
For Testing Paint, Varnish, Conversion Coatings, and
3 tions known to be conducive to filiform corrosion.
Related Coating Products
4.2 In Procedure A, panels are subjected to a preliminary
D 823 Test Methods for Producing Films of Uniform Thick-
exposure in the salt spray cabinet to initiate corrosion, rinsed,
ness of Paint, Varnish, and Related Products on Test
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and placed in a humidity cabinet. In Procedure B, based on ISO
Panels
4623, panels are either exposed to salt spray or dipped in a salt
D 1005 Test Method for Measurement of Dry-Film Thick-
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solution but not rinsed before placing in the humidity cabinet
ness of Organic Coatings Using Micrometers
operated at a higher temperature than in Procedure A. In
D 1186 Test Methods for Nondestructive Measurement of
Procedure C, specimens are exposured as in Procedure A
Dry Film Thickness of Nonmagnetic Coatings Applied to
3 except the humidity cabinet is operated at a higher temperature.
a Ferrous Base
D 1400 Test Method for Nondestructive Measurement of
5. Significance and Use
Dry Film Thickness of Nonconductive Coatings Applied to
3 5.1 Some organic coatings applied to metal substrates ex-
a Nonferrous Metal Base
hibit filiform corrosion when there is a break in the coating film
D 1654 Test Method for Evaluation of Painted or Coated
3 and the relative humidity is in the 70 to 95 % range.
Specimens Subjected to Corrosive Environments
5.2 This guide can be used to determine the susceptibility of
D 1730 Practices for Preparation of Aluminum and
4 organic coated metal substrates to the formation of filiform
Aluminum-Alloy Surfaces for Painting
corrosion.
E 104 Practice for Maintaining Constant Relative Humidity
6. Apparatus
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This guide is under the jurisdiction of ASTM Committee D-1 on Paint and
6.1 Salt-Spray Chamber as described in Test Method
Related Coatings, Materials, and Applications and is the direct responsibility of
B 117, for salt-spray (fog) testing.
Subcommittee D01.27 on Accelerated Testing.
Current edition approved May 15, 1993. Published July 1993. Originally
published as D 2803 – 69 T. Last previous edition D 2803 – 82 (1987).
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Annual Book of ASTM Standards, Vol 03.02.
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Annual Book of ASTM Standards, Vol 11.03.
3
Annual Book of ASTM Standards, Vol 06.01.
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Available from American National Standards Institute, 11 W. 42nd St., 13th
4
Annual Book of ASTM Standards, Vol 02.05.
Floor, New York, NY 10036.
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D 2803
NOTE 1—The preferred initiator of corrosion at the scribe is the salt-fog
of filament growth in direction, width, height and frequency
atmosphere described in Test Method B 117. Exposure of the specimens
precludes a precise rating system. Photographs of filiform
for2to4hina closed cabinet to the atmosphere above a 1 % acetic acid
failure are preferred for recording test results. Otherwise, a
soluti
...