ASTM D2803-09(2020)
(Guide)Standard Guide for Testing Filiform Corrosion Resistance of Organic Coatings on Metal
Standard Guide for Testing Filiform Corrosion Resistance of Organic Coatings on Metal
SIGNIFICANCE AND USE
5.1 Some organic coatings applied to metal substrates exhibit filiform corrosion when there is a break in the coating film and the relative humidity is in the 70 to 95 % range.
5.2 This guide can be used to determine the susceptibility of organic coated metal substrates to the formation of filiform corrosion.
SCOPE
1.1 This guide covers three procedures for determining the susceptibility of organic-coated metal substrates to formation of filiform corrosion.
1.2 This guide is limited to the determination of whether filiform corrosion will occur between the organic coating and substrate.
1.3 The values stated in SI units are to be regarded as the standard. The values given in parentheses are for information only.
Note 1: Procedure B of this standard is equivalent to ISO 4623.
1.4 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use.
1.5 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
General Information
Relations
Standards Content (Sample)
This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the
Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
Designation: D2803 − 09 (Reapproved 2020)
Standard Guide for Testing
Filiform Corrosion Resistance of Organic Coatings on
Metal
This standard is issued under the fixed designation D2803; 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 (´) indicates an editorial change since the last revision or reapproval.
This standard has been approved for use by agencies of the U.S. Department of Defense.
1. Scope D1005 Test Method for Measurement of Dry-Film Thick-
ness of Organic Coatings Using Micrometers
1.1 This guide covers three procedures for determining the
D1654 Test Method for Evaluation of Painted or Coated
susceptibility of organic-coated metal substrates to formation
Specimens Subjected to Corrosive Environments
of filiform corrosion.
D1730 Practices for Preparation of Aluminum and
1.2 This guide is limited to the determination of whether
Aluminum-Alloy Surfaces for Painting
filiform corrosion will occur between the organic coating and
D7091 Practice for Nondestructive Measurement of Dry
substrate.
Film Thickness of Nonmagnetic Coatings Applied to
1.3 The values stated in SI units are to be regarded as the Ferrous Metals and Nonmagnetic, Nonconductive Coat-
ings Applied to Non-Ferrous Metals
standard. The values given in parentheses are for information
only. E104 Practice for Maintaining Constant Relative Humidity
NOTE 1—Procedure B of this standard is equivalent to ISO 4623. by Means of Aqueous Solutions
1.4 This standard does not purport to address all of the
2.2 International Standard:
safety concerns, if any, associated with its use. It is the
ISO 4623–1 Paints and Varnishes—Determination of resis-
responsibility of the user of this standard to establish appro-
tance to filiform corrosion–Part 1: On steel
priate safety, health, and environmental practices and deter-
ISO 4623–2 Paints and Varnishes—Determination of resis-
mine the applicability of regulatory limitations prior to use.
tance to filiform corrosion–Part 2: On aluminum
1.5 This international standard was developed in accor-
ISO 4628–10 Paints and Varnishes—Evaluation of degrada-
dance with internationally recognized principles on standard-
tion of coatings—Designation of quantity and size of
ization established in the Decision on Principles for the
defectsandofintensityofchanges–Part10:Assessmentof
Development of International Standards, Guides and Recom-
filiform corrosion
mendations issued by the World Trade Organization Technical
Barriers to Trade (TBT) Committee. 3. Terminology
3.1 Definitions:
2. Referenced Documents
3.1.1 filiform corrosion, n—a special type of corrosion that
2.1 ASTM Standards:
occurs under coatings on metal substrates that is characterized
B117 Practice for Operating Salt Spray (Fog) Apparatus
by a definite threadlike structure and directional growth.
D609 Practice for Preparation of Cold-Rolled Steel Panels
3.1.1.1 Discussion—Filiform corrosion usually occurs be-
for Testing Paint, Varnish, Conversion Coatings, and
tween 20 and 35°C (70 and 95°F), with a corresponding
Related Coating Products
relative humidity range of 60 to 95 %; above 95 % humidity,
D823 Practices for Producing Films of Uniform Thickness
blistering rather than filiform corrosion may occur.
of Paint, Coatings and Related Products on Test Panels
4. Summary of Method
This guide is under the jurisdiction of ASTM Committee D01 on Paint and
4.1 Coated metal specimens are scribed and placed in a
Related Coatings, Materials, and Applications and is the direct responsibility of
corrosive atmosphere to initiate corrosion. The specimens are
Subcommittee D01.27 on Accelerated Testing.
then exposed to controlled temperature and humidity condi-
CurrenteditionapprovedJune1,2020.PublishedJuly2020.Originallyapproved
in 1969. Last previous addition approved in 2015 as D2803 – 09 (2015). DOI:
tions known to be conducive to filiform corrosion.
10.1520/D2803-09R20.
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
Standards volume information, refer to the standard’s Document Summary page on Available from American National Standards Institute (ANSI), 25 W. 43rd St.,
the ASTM website. 4th Floor, New York, NY 10036, http://www.ansi.org.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
D2803 − 09 (2020)
4.2 In Procedure A, panels are subjected to a preliminary 8. Use of Control or Reference Materials
exposure in the salt spray cabinet to initiate corrosion, rinsed,
8.1 When several coatings are being compared, select a
andplacedinahumiditycabinet.InProcedureB,basedonISO
coating as a control. Apply the control coating to the same
4623, panels are either exposed to salt spray or dipped in a salt
substrate as the test coatings. For best results there should be
solution but not rinsed before placing in the humidity cabinet
two controls, one known to perform well and one known to
operated at a higher temperature than in Procedure A. In
perform poorly.
Procedure C, specimens are exposed as in Procedure A except
the humidity cabinet is operated at a higher temperature.
9. Procedure A
4.3 The procedures contained in this guide differ signifi-
9.1 Expose the test specimens to the salt-fog atmosphere in
cantly in method of initiation, and or temperature, or both, and
accordance with Practice B117 for at least 4 h and not more
humidity of exposure and therefore may not yield comparable
than 24 h, or as agreed upon between the producer and user.
results.
9.2 Remove from the salt-fog cabinet and thoroughly rinse
5. Significance and Use
with distilled or demineralized water. Do not permit specimens
to dry before placing in the humidity cabinet.
5.1 Some organic coatings applied to metal substrates ex-
hibitfiliformcorrosionwhenthereisabreakinthecoatingfilm
9.3 Place the specimens in the humidity cabinet so that they
and the relative humidity is in the 70 to 95 % range.
are no closer together than 40 mm (1.5 in.) and not in contact
with any metal. Set the cabinet to operate at 25°C (77°F) and
5.2 This guide can be used to determine the susceptibility of
85 % relative humidity unless otherwise agreed upon between
organic coated metal substrates to the formation of filiform
theproduceranduser.Theallowedoperationallimitsare 62°C
corrosion.
(63.5°F) and 610 % relative humidity.
6. Apparatus
NOTE6—Therecommendedmeansofmaintainingthespecifiedrelative
humidity is to utilize trays of saturated potassium chromate solution (650
6.1 Salt-Spray Chamber as described in Practice B117, for
g/L). Practice E104 describes other methods for maintaining relative
salt-spray (fog) testing.
humidity, but they may affect the degree and rate of filiform corrosion.
NOTE 2—The preferred initiator of corrosion at the scribe is the salt-fog
9.4 In
...
Questions, Comments and Discussion
Ask us and Technical Secretary will try to provide an answer. You can facilitate discussion about the standard in here.