10 YEARS’ EXPOSURE AT GELEEN, THE NETHERLANDS

Relative performance differences in this inland industrial environment are less dramatic, but still substantial

55% Al-Zn	Galfan	Hot-dip galvanised

45º South: polyester coatings. After 10 years, the 55% Al-Zn and hot-dip galvanised panels show virtually no failure. The Galfan (Zn-5% Al) panel has suffered paint loss on the bend and the edges.

55% Al-Zn	Galfan	Hot-dip galvanised

5º South: polyester coatings. This configuration provides a very severe test. None of the panels, however, display appreciable corrosion; but the Galfan and hot-dip galvanised specimens show paint loss along the edges.

55% Al-Zn	Hot-dip galvanised

5º South: Pvdf coatings. The hot-dip galvanised panel shows appreciable paint delamination on the overlap and at the sheared edges. The 55% Al-Zn panel is in good condition, except for some staining on the bend.

55% Al-Zn	Hot-dip galvanised

45º South: silicon modified polyester (SMP) coatings.

55% Al-Zn	Hot-dip galvanised

5º South: SMP coatings

55% Al-Zn	Hot-dip galvanised

90º North: SMP coatings

The SMP topcoat is brittle (less formable) than polyester, and is expected to exhibit more micro-fracturing on bends. This effect is well documented above. Whilst the 55% Al-Zn panels show staining on the variable radius bend for all three exposure orientations, no substrate corrosion (red rust) can be observed. The galvanised panels all show varying degrees of red rust on the V-bend, on sheared and overlapped edges, and around fasteners.
2 panels, 55% Al-Zn and Hot-dip galvanised