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Reference Object No 4 |
In the maintenance and corrosion control of steel structures in the industrial sector (e.g. chemical plants, steelworks etc.) it is not normally possible to remove old coatings completely or to fully derust surfaces (e.g. by sandblasting).
In cooperation with DOW Chemical in Stade, laboratory and practical tests were conducted to investigate whether CORRPASSIV® primers were suitable for use on rusted surfaces. The requirement was to combine CORRPASSIV® Primer, which had to be "surface-tolerant", with a suitable topcoat system. The aim was to prevent further corrosion despite inadequate preliminary treatment of the surfaces.
A comprehensive programme of comparison with commercially available "surface-tolerant" coatings was first performed on manually derusted St-14 test plates for 1200 hours in a VDA alternating test 621-415. The results were so promising that in August 1997 large areas of several structural elements (pipeline gantries, superstructures, stairways) on the factory site were treated with the best CORRPASSIV® system for a practical test. A photo documentation of this work will follow shortly.
The evaluation of the VDA alternating test weathering after 1200 hours showed that a coating system with a CORRPASSIV® primer and a suitable topcoat (in the form of the CORRPASSIV® 4905 system) yielded the best results. The coating was applied to manually derusted (ST 3) St-14 test plates which did not undergo any further cleaning.
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| Fig. 1 shows manually derusted test plates treated with a leading international manufacturer's tried-and-tested system which is well established on the market. Under-film creep and blistering are clearly visible in the vicinity of the injury. | Fig. 2 shows CORRPASSIV® 4905, also on manually derusted plates. There is virtually no under-film creep or blistering to be seen. The surface structures on the left of the picture are due to the rusted surface to which the coating was applied. |
CORRPASSIV® 4905 is outstandingly suitable for refurbishing rusty industrial structures after light mechanical rust treatment and may be classified as "surface-tolerant".
Ormecon Chemie GmbH & Co. KG
- ein Unternehmen der Zipperling Kessler & Co. (GmbH & Co.) -
Ferdinand-Harten-Str. 7 • D-22949 Ammersbek • Tel.: +49-(0)40-604106-0 •
Fax: +49-(0)40-604106-51
