Coating defect

Delamination (intercoat adhesion failure)

A coat parts from the coat below in sheets or patches. The coat underneath shows a smooth, clean surface in its own colour.

Delamination (intercoat adhesion failure): the surface as you see it, and a schematic cross-section.

Causes

The maximum recoat window was exceeded and the old coat was not roughened.
Contamination between coats: dust, salts, grease, condensation or amine blush.
Incompatible coats.

Prevention

Recoat within the window, or sweep blast or abrade the old coat when the window has passed.
Clean and check each coat before the next.

How it is assessed

Adhesion tests (cross-cut, X-cut or pull-off) and the failure mode: note at which interface the coat parted.

Telling it apart

Peeling: Peeling lifts a whole soft film, often from the substrate. Delamination is one coat parting cleanly from the coat below.
Amine blush: A blushed epoxy that was overcoated without washing is a common cause of delamination.

Repair

Remove loose coating to firmly adhered coating, feather the edges, roughen the sound coating around it, clean, and recoat. The specification and the coating manufacturer have the final word on the repair procedure.

12 practice items in the members area mention delamination (CIP 1: 3 · CIP 2: 4 · FROSIO written: 5).

Try it in an exam-style question. The free readiness check shows the question style, explains every answer and gives you a dated study plan.

Take the free readiness check See the tracks

About this page

Written from coating practice and the published rating standards, in our own words; the drawing is schematic. Checked on 2026-10-14; errors go in the corrections log. CoatMentor is an independent study aid. It is not affiliated with ISO, AMPP, SSPC, NACE International, ASTM or FROSIO.