BS EN ISO 4623-1:2018 pdf download.Paints and varnishes - Determination of resistance to filiform corrosion Part 1: Steel substrates.
10.3.1 General
Two alternative procedures are available, based on initiation by dipping in sodium chloride solution orby exposure to salt fog.The dipping technique is generally preferable for air-drying and low-durabilitymaterials. For high-durability systems such as automobile finishes applied to phosphated steel, thedipping technique may not produce filiform corrosion and for these systems it is preferable to adoptthe salt fog technique. In such cases, the necessary period of exposure to salt fog will depend on thedurability of the material under test but should rarely need to exceed 4 h. lt should be noted that saltfog exposure is not normally suitable for low-durability materials since with such systems it commonlyproduces heavy general corrosion spreading from the scribed marks and the filiform corrosionis suppressed.
10.3.2 Dipping technique
lmmerse the scribed test panels for 30 s to 60 s in the sodium chloride solution(8.1).
Take the panels out of the solution and remove any drops of liquid remaining on the surface, taking carenot to remove the solution from the scribed marks.
Place the panels in the test cabinet (zZ.1) maintained at (40± 2) °Cand a relative humidity of (80± 5)%.Repeat the immersion procedure, as specified above, every 3 or 4 days until the end of the specifiedtest period.
10.3.3 Salt fog technique
Expose the scribed test panels to neutral salt fog as described in ISO 9227 for the specified period.Take the panels out of the salt fog cabinet and remove any drops of liquid remaining on the surface,taking care not to remove the solution from the scribed marks.
