Water can be the most detrimental factor in an environment to a coating system, especially at elevated temperatures. Water molecules will diffuse through the coating to the substrate. If the water collects at the coating/substrate interface, it may potentially cause loss of adhesion. If the adhesion between the coating and the substrate are significantly reduced, the coating may disbond and could shield cathodic protection and the substrate would be vulnerable to corrosion or could break off exposing the substrate. The Soak Adhesion Test examines a coating’s ability to adequately adhere to the steel in immersion conditions. During the test procedure test specimens are placed on the supports in a temperature controlled water bath and submerged fully in the preheated water. . After concluding the submersion test, the specimens are removed from the container and approximately 30 ×15 mm rectangle is scribed through the coating to the substrate. Using utility knife adhesion of the coating is examined and the coating adhesion resistance is rated.
- The test specimen typically 100 mm × 100 mm × 6.4 mm
- CSA Z245.20
- ISO 21809-2
- ISO 21809-3
Soak Adhesion Assessment after Submersion