Failure mode in which the coating separates cleanly from the substrate, leaving bare, blasted metal on the test button. It points to problems at the bond line: contamination, low profile, flash rust, oxidized bond coat or excessive stress. Specs often require not only a minimum strength but also that failures are not adhesive.
Heard on the job
Adhesive failure on all three buttons, bare grit-blasted metal, go look at the blast cabinet.
Also heard as
- interface failure
- adhesion failure
Do not mix it up with
- Cohesive failure: Adhesive failure is at the coating-substrate interface, while cohesive failure breaks inside the coating itself.
Related terms
Bond strength
How hard you must pull to tear a coating off its substrate, measured by gluing and tensile testing.
Cohesive failure
A bond test break inside the coating, with coating left on both halves of the test specimen.
Bond line
The interface between a sprayed coating and the substrate, or between two coating layers.