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


-----

Aluminum oxide removal

I have some unanodized aluminum parts that had some exposure to salt water and were heavily oxidized. Is there any chemical that will remove this oxide layer?

James McPherson
Nova Analytical Systems Inc - Niagara falls, New York
2001

I wanted to know what the answer was. I have a situation that is similar.

Ray Swick
- Lincoln, Nebraska, USA
2004

I also have some aluminum which has been oxidized by salt water and would like to know of any chemicals or treatment to remove it.

Larry Holt
- Belle Haven, VA, USA
2005

---

2006

Al metal and primary alloys are fairly soft. You can polish this to your liking.

Two points to clarify. Yes there are chemical treatments to remove the oxide layer. Something like Hydrofluoric Acid will probably work, but HF is pretty nasty and the 2nd point below is probably the more important thing.

Even if you could possibly remove the oxide layer, Aluminum has such a high affinity for oxygen that Al2O3 will reform in a normal STP environment, in less than 1 ten thousandth of a second. So, it won't really matter if you remove the oxide layer. The layers that form can be different thicknesses, but are on the order of 1x10^-10. Or a few atoms thick. Anodizing can increase this layer but again, even if the layer was removed... blink and its back again. You can practically rub junk into the surface to make it shiny though.

Sparky Webster
- Des Moines, Iowa, US