Painting nitride surface

[Rickdeec]

Need advice on prepping for paint a small metal part that has been through a nitride process. Also, any suggestions on paint type and curing method? Painted area is only .10" diameter dot, but subjected to heat and recoil motion.

 

[tbuelna]

The nitriding does not present any issues with applying paint to the surface. But the small area the paint will be applied to might cause some problems. If the paint is only applied to a .10" diameter location, I'd suggest machining a shallow hole of this size that can be filled with the paint. This will make applying the paint easy and will make the paint dot less susceptible to damage.

 

[Rickdeec]

tbuelna,

We are painting the nitride part now, and the primer paint is falling during use of the part. We are using same paint as past ten years, only difference is prior parts were black oxide instead of nitride.

 

[CoryPad]

Can you describe the failure mode? Any chance the nitrided parts are larger in diameter (nitride surface layer thicker than black oxide) and this is in more contact with mating surfaces, leading to paint damage?

 

[tbuelna]

Rickdeec-

Are you prepping the nitrided surface properly for paint? It may be necessary to mask the surrounding area and mechanically abrade (light grit blast or similar) the .10" dia surface to get best paint adhesion. You might also consider laser engraving a shallow depression (~.001" deep) for the paint dot, provided the dot is not located in a sensitive area. This will help protect the edge of the paint dot from peeling.

As for other coating options, there are some very durable mil-spec epoxy ink compounds designed specifically for part marking on metal surfaces.

Hope that helps.
Terry