ASTM D2803 – Filiform Corrosion Resistance of Organic Coatings on Metal
Filiform corrosion refers to thread-like filaments of corrosion that typically form under thin organic coatings in a process accelerated in high humidity environments and slightly elevated temperatures. Filiform corrosion attacks a variety of metals including aluminum, magnesium, and steel. This test determines susceptibility of coated metal surfaces to the formation of filiform corrosion.
This test offers three options. All three begin by scribing a coated metal panel and placing it in a salt spray chamber to start corrosion formation. Procedure A removes the panel from the salt spray chamber, rinses it and places it in a humidity cabinet for the remainder of the test. Procedure B removes the panel from the salt spray chamber and places it in a humidity cabinet, but panels are not rinsed between chambers. Procedure C is the same process as Procedure A, but with a high temperature humidity cabinet. Reported is a pass if no filiform corrosion is present, or as fail if corrosion is present and any observations.