PVD-based TiN coating over Ni substrate?

[coreman73]

I'm trying to find out what type of coating technology might have been used on a small snip blade cutting tool. EDS results clearly indicate the 1st layer (directly on surface) is Ni. The layer on top of this appears to be TiAlCrN so was most likely created by PVD coating process.

It's my understanding that PVD coatings have a deposition temperature of around 700-800 degrees F. My question is how could this layer have been applied without negatively affecting/tempering the below Ni layer and Fe base metal?

I would appreciate any advice very much.

 

[TVP]

If the tool steel used for the blade exhibits secondary hardening characteristics (high speed steels like M2, M4, M48, etc. that are alloyed with Co, Mo, W, and/or V), then the tempering temperature is > 700-800 F. For example, M4 develops maximum hardness when tempered around 1000 F. Here is a datasheet from Latrobe Steel for M4:

http://www.latrobesteel.com/assets/documents/datasheets/Stark.pdf

 

[coreman73]

Thanks for the response and link TVP.

The chemical analysis results of the base material seem to indicate a carbon steel of grade 1060 was used. However, there are additions of Si (.28 wt%), Cr (.23 wt%) and Mo (.20 wt%). Could it be possible that this is some sort of modified steel that would require a tempering temperature above 700-800 F like you mention? Sorry, I should have included this info with my original post.