Abstract
The demands on protective coatings used in offshore environments are very high and modern high performance paint systems are so durable that when exposed to natural weathering they may show only slight signs of deterioration. The best anticorrosive coating systems of today may continue to perform well for maybe 15-20 years. The use of new technologies also means that coatings being marketed have limited track record. This has resulted in a necessary increase in reliance on accelerated laboratory testing to evaluate coating performance. However, many of these accelerated exposure tests will not, within their exposure time, show negative effects on intact coating systems. Therefore rust creep from artificially made damage is receiving significant consideration. Rust creep, according to the existing standards, is evaluated by a ruler after removal of the paint around the score. This evaluation method is destructive which means that one panel only gives one reading of rust creep and in addition the method is rather time consuming. This paper presents a new non-destructive test (NDT) method which makes it possible to record the progress of rust creep during the exposure time without removing the paint. The advantages of using this method are that the same panels can be investigated several times during the exposure time; the method is fast and exact and it provides early prediction of the final rust creep.
