"Adhesion" is defined as the sum of the adhesion forces between a dry paint film and its substrate (Ref: AS/NZS 2310: Glossary of terms for paints and coatings).
Loss of adhesion can be pictured or described in many different ways. A gradual loss of adhesion may occur as degradation increases through the following stages (also as defined by AS/NZS 2310).
Inspection - Cracks in the surface of the paint film that do not visually reveal the underlying surface when the film is viewed at 10X magnification. (See AS 1580.481.1.7 for assessment of inspections).
CRAZING - The formation of tiny criss-cross cracks in the surface of the paint film. Cracks are similar to "checks", but the cracks are deeper/wider and they take on a polygonal pattern similar to crazy paving.
Cracking - Formation of defined breaks in the paint film that actually expose the substrate.
Blistering - A raised deformation of a paint film caused by localized detachment of one or more constituent coatings or layers.
Peeling - Localized loss of adhesion between the paint film and the substrate or partial detachment of the substrate in the area of the paint film due to loss of adhesion.
Fade - Complete separation of the paint film from the underlying surface or substrate.
