76
Fundamentals of Corrosion
of product integrity only when it occurs on thin sheets (~0.05 mm or thinner) and foil (defined as ≤0.15 mm in thickness (e.g., food containers, or a foil
moisture barrier on insulation board or on foil-laminated paper packaging).
On thicker painted sheet, as for aircraft and automobiles, filiform corrosion is primarily a cosmetic problem, but it causes loss of paint adhesion and
can act as a site initiation of pitting or other forms of corrosion.
3.14.1 Preventive Measures
Filiform corrosion can be prevented by reducing the humidity of the environment to below 65%. Films having a very low permeability will also provide
protection. Other important factors that can determine whether this form
of corrosion will occur include preparation of the metal surface for coating;
surface cleanliness; coating flexibility, thickness, and adherence; and the
absence of voids.
References
1. Schweitzer, P.A., 2004, Corrosion Resistance Tables, 5th edition, Vols. 1–4, New
York: Marcel Dekker.
2. Schweitzer, P.A., 2004, Encyclopedia of Corrosion Technology, second edition, New
York: Marcel Dekker, p. 197.
3. Schweitzer, P.A., 2004, Encyclopedia of Corrosion Technology, second edition, New
York: Marcel Dekker, p. 570–571.
4. Schweitzer, P.A., 2004, Encyclopedia of Corrosion Technology, second edition, New
York: Marcel Dekker, p. 326.
5. Schweitzer, P.A., 2004, Encyclopedia of Corrosion Technology, second edition, New
York: Marcel Dekker, p 444.
6. Schweitzer, P.A., 2004, Encyclopedia of Corrosion Technology, second edition, New
York: Marcel Dekker, p 298.