Moisture permeability test

The water migration test shows you whether the coating is tight or whether water penetrates through pores and holes down to the material. If the test fails, the layer is not tight enough – this leads to corrosion and cracks and the component won't last long. You check this according to common standards by exposing the coated surface to damp heat for a certain time. If moisture comes through afterwards, the coating is simply faulty and you have to reapply it.