Rust creep assessment - A comparison between a destructive method according to ISO 12944 and selected non-destructive methods

Rust creep is one of the most important criteria for the prequalification of anti-corrosive coating systems for offshore applications. The standard method for rust creep evaluation, as established in ISO 12944-9, is destructive in nature, which means that one panel only gives one reading of rust creep due to the removal of the coating beyond the rust area. Non-destructive methods allow for the evaluation of coating performance in a faster and more cost-effective way, i.e. the same coated panel can be tested over time and the propagation of the rust creep can be detected and monitored. In the present work, three methods based on ISO 12944-9, optical 3D Profilometry and Scanning Acoustic Microscopy (SAM) for rust creep assessment are compared and results show that the optical 3D Profilometry and SAM can act as complementary non-destructive tools which can provide efficient rust creep monitoring.