Avflaking

Avflaking is a failure mode in layered materials in which fragments of a surface coating or top layer detach as flakes from the substrate. The term is used in materials science and coatings engineering to describe coarse-scale delamination and shedding that can occur under mechanical stress, thermal cycling, moisture ingress, or UV exposure. The process typically begins at an interface where adhesion is weakest, such as between the substrate and the first coating, or within a coating layer that has internal defects or residual stresses. Once initiated, cracks propagate laterally, producing visible flakes that can vary in size from a few micrometers to several millimeters. The phenomenon is distinct from uniform wear or pigment powdering because it involves discrete fragments and delamination across a surface.

Avflaking is commonly observed in protective paints and polymer coatings on metal or composite substrates, in ceramic or multilayer optical coatings, and in decorative finishes. Factors contributing include poor surface preparation, incompatible coating systems, accelerated aging environments (high humidity, salt spray, UV), excessive film thickness, and thermal mismatch between layers. Detection methods include visual inspection, cross-sectional microscopy, adhesion testing (pull-off, peel tests), and non-destructive evaluation techniques.

Prevention strategies center on improving interfacial adhesion and coating performance: proper surface pretreatment, choosing compatible coating systems, controlling cure schedules, employing barrier or primer layers, and applying coatings within specified thicknesses. Remediation may require surface grinding or removal of affected areas, re-coating with improved systems, or replacing damaged components. In research contexts, avflaking is studied alongside delamination, cohesion failure, and spallation to inform more durable coatings.