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5346 |
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Wednesday, June 07, 2017, Hall Y 2:40 PM Maritim Industry & Off-Shore Technologies |
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Partial repair of thermally-sprayed and sealed corrosion protection organic coating material or thermal spraying? |
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Thomas Wilhelm* / GSI mbH, Branch SLV Duisburg, Germany Teodora Maghet / GSI mbH, Branch SLV Duisburg, Germany Monica Sallai/ GSI mbH, Branch SLV Duisburg, Germany Jörg Mährlein/ GSI mbH, Branch SLV Duisburg, Germany Susanne Friedrich/ Institut fuer Korrosionsschutz Dresden GmbH, Germany Romy Regenspurger/ Institut fuer Korrosionsschutz Dresden GmbH, Germany Ralf Feser/ University of Applied Sciences South Westphalia, Germany Christian Klesen/ GSI mbH, Branch SLV Duisburg, Germany |
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Thermally sprayed corrosion protection systems on the basis of ZnAl or Al are not a new invention. For many decades they carry out their service for structures in coastal areas, the offshore sector, as CUI (Corrosion Protection under insulation) or anywhere where the properties of thermally sprayed corrosion protection systems bring important advantages in terms of durability. A thermally sprayed corrosion protection system is about to protect the structure 25 to 30 years against corrosion. During this time it may be damaged due to many factors such as construction work, improper handling or simple aging. There are many standards and regulations, which describe the initial design of thermal spray systems. In particular, a mending of partial regions is hardly described. Specific repair instructions are rare and if present, they differ from one another. Overall there is a lack of knowledge of the proper procedures for partially repairing thermal spray coating systems. A completed research project and one ongoing research project were concerned with tangible corrosion-technical issues of manufacture and repair of sealed thermal sprayed ZnAl and Al coatings: Which influence has the sealer viscosity on the coating penetration? How does the critical overlap between original and repaired coating area perform? Have organic coatings benefits for partial repairs? The aim of these studies is to develop practice-relevant instructions for manufacture and repair of thermally sprayed duplex systems. These substrates were therefore protected with ZnAl15, Al99 and were finally sealed. To work as practical as possible, these layers were aged, i.e. stored in the salt spray test. Reference coating performances came from a real offshore construction. The results show the influence of surface preparation, repair methods and the overlapping width between original and new area on the corrosion behavior of thermally sprayed corrosion protection coatings. Furthermore, practical advices for partial coating repairs were derived. |