The Corrosion of Zirconium

Zirconium alloys exhibit excellent resistance to corrosive attack and works well in many organic and inorganic acids, salt solutions, strong alkalies, and some molten salts.

Zirconium owes its corrosion resistance to the natural formation of a dense, stable, self-healing oxide film on its surface. Unalloyed zirconium has excellent corrosion resistance to sulfuric acid up to 60% concentration at the boiling point and has excellent corrosion resistance in hydrochloric acid.  

Zirconium is also highly resistant to most alkali solutions up to their boiling point. Zirconium’s corrosion resistance could be compared with titanium in many ways; however zirconium is much more robust than titanium in withstanding organic acids, such as acetic, citric, and formic acids at various concentration and elevated temperatures.

For all of zirconium’s attributes it still can be corrosively attacked by fluoride ions, wet chlorine, aqua regia, concentrated sulfuric acid above 80% concentration, and ferric or cupric chlorides.