Where the
world gathers for metal finishing
Q&As since 1989


-----

Corrosion resistance of zinc/iron alloys

During hot dip galvanizing, different zinc iron alloys are formed. I am wondering what the corrosion resistance of the different zinc iron alloy layers is.

I can't imagine that they are all the same.

Jelle Elbers
hot dip galvanizing company - Maarssen, Utrecht, The Netherlands
2003

---

When you look at the alloy layers in normal job galvanizing build-up is in four layers, seen from the steel: three zinc-iron alloy layers: Gamma-layer (21-28% iron), Delta-layer (6-17% iron), Zeta-layer (6% iron) and the eta-layer (pure zinc). However, practice shows that corrosion resistance will not be reduced when the pure zinc layer has disappeared and the alloy layer is reached and will be even higher in some cases, although the material will show a rust-brown coulor sometimes. The reason is too complex to explain in short.

Dolf van den Berg
- Leusden, The Netherlands
2003