Visual evaluations are the core of coating evaluations after testing. We will take a look at the coating surface by means of the unaided eye or by means of stereomicroscopy to search for defects in the coating or any indications of coating degradation. On top of that, results of other measurements like gloss/color can indicate that coating degradation has taken place. It is possible that corrosion proceeds underneath the coating.
To measure how well coating systems resist against this ‘creep’, an artificial defect under the form of a scratch (scribe) is typically applied to the test panels/product before (cyclic) salt spray testing. Afterwards the extent of creep starting at the scratch is determined by dimensional measurements before and after scraping off the coating.
The adhesion of a coating depends much on the pretreatment of the surface before coating and is a major factor of coating failure in practice. Adhesion tests can be performed before and after accelerated corrosion tests to test the impact of exposure conditions to the adhesion of the coating on the substrate.
Beside the evaluations mentioned above METALogic also performs other evaluations like dry film thickness measurements, bend test, cupping test, impact test, pencil hardness test, … . A (non-exhaustive) list of standards that METALogic can perform you will find below: