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Reference Object No 3 |
The constructional steel grids to be coated are used to cover dung pits in cowsheds. In the past, conventional coating materials have only proved effective when applied in a film thickness of several hundred µm. For reasons of time and cost, this is not practicable on farms, especially since it makes the coatings correspondingly brittle. Untreated grids corrode in the first few weeks after installation. Continuing exposure gives rise to substantial depletion due to rust, which reduces the thickness of the steel to as little as half its original thickness, thereby significantly reducing its mechanical load-bearing capacity.
Exposure to faecal matter subjects the grids to heavy corrosion. Considerable mechanical wear is also caused by the cows’ hooves and the shovels used for cleaning.
Derusting of the corroded grids was by means of sandblasting (SA 2 ½). Then CORRPASSIV® primer was applied with a thickness of 20 µm and CORRPASSIV® two-component epoxy sealer with a thickness of ## µm.
A control grid was left uncoated.
After nearly 3 years’ use in practice the grids were removed from the cowshed in summer 1997 for assessment.
CORRPASSIV® 4900 passed the test with flying colours: no rust occurred!
The underside of the control grid that was derusted but not coated three years before. The top likewise displayed total rusting due to the action of faecal matter.
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The top of the grid treated with CORRPASSIV® 4900. Owing to the mechanical wear caused by the animals’ hooves and the shovels used for cleaning twice a day, the coating was completely removed - but even then there was no rust!
The underside of the grid coated with CORRPASSIV® 4900 does not exhibit any corrosion either, especially because it remained undamaged because of the lack of mechanical wear. But the chemical resistance of the coating to the aggressive media is remarkable.
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
