Zirconium Nitride (ZrN) 

The silvery-gold colored zirconium nitride (ZrN) is a somewhat harder and smoother coating than TiN. 

It also has a higher oxidation resistance. 

ZrN is a more expensive coating with a considerably longer lead time, but this difference is often offset and justified by its higher cutting performnce, especially in finishing operations. 

Some users report excellent finishing performance in abrasive work materials on lightly honed high speed steel and carbide tools with small edge radii.