Coatings and Cathodic Disbondment The True Story
Damage to pipe coating is almost unavoidable during transportation and construction and damage or holidays in pipe coatings may expose the pipe to possible corrosion. Cathodic protection systems are installed to act as a back-up for coating imperfections. However, cathodic protection systems interact with the coating by chemical and physical phenomena, which can lead to cathodic disbondment of the coating. Corrosion may occur underneath the disbonded coating, which is a risk for pipeline owners. Testing for cathodic disbondment of all types of ”conventional coatings” often reveal disbondment to a certain extent. Contrary to this, Properly formulated visco-elastic polymer coating systems do not show any disbondment at all, due to the unique self-healing effect of small defects.Testing for cathodic disbondment is always done on newly applied coatings and are only tested for a short period of time, e.g. 30 days. Lifetime expectancy of pipelines however are much longer, typically 30 years or more. During its operating lifetime a coating will age and lose essential properties such as adhesive strength. This can be simulated by Hot Water Immersion testing followed by peel-testing. Results obtained with cathodic disbondment testing do not make much sense if over time the coating spontaneously disbonds because of the coating”s ageing processes.Stopaq visco-elastic coating systems have proved not to be vulnerable to ageing in Hot Water Immersion tests; values obtained with peel testing after Hot Water Immersion at Tmax + 20? for 100 days were similar to values obtained with non-aged test specimens and the self-healing effect - a typical property of Stopaq coating systems - still completed within the expected period of time.
Coating Testing Cathodic Disbondment Shielding Ageing Hot Water Immersion
Erik Broesder K.C.Lax
Stopaq b.v Gasselterstraat 20 9503 JB,Stadskanaal the Netherlands Asset Integrity Services Ltd.5 Jupiter House,Calleva Park.,Aldermaston,RG7 8NN United Kingdom
国内会议
上海
英文
69-73
2012-10-01（万方平台首次上网日期，不代表论文的发表时间）