Scratch Testing of Coatings

Scratch testing is a test method used to characterise the adhesion of surface coatings.

The test involves drawing a hard tool (indenter) across the surface coating with increasing load, whilst using a calibrated load cell to record the measurements applied.  At a critical force, the coating will either delaminate from the substrate or the indenter will cut through to the substrate below, depending on the coating properties and the indenter used.

The test tool position during testing is critical for accurate and repeatable test results. Nordson DAGE uses precision XY stages and test cartridges with calibrated load cells, which provide repeatable measurements of the downward force across the full length of the test scratch.