"Chrome hydraulic cylinder rods?

[nova3930]

But I'm wondering why a nitrided rod would have more tendency to break? Its as if the nitriding process creates microscopic stress risers in the rod surface. I am still, however, wondering about hydrogen embrittlement of the rod surface which is what some plating operations produce.

I would suspect it's more about the nitriding process affecting the heat treat of the base material since it occurs at elevated temperature.

I'm surprised nobody is doing PVD coatings on hydraulic cylinders. Rods coating with TiAlN via PVD would be superior to bright electroplated chrome in basically every physical category...

 

[wdchyd]

………..I'm surprised nobody is doing PVD coatings on hydraulic cylinders. Rods coating with TiAlN via PVD would be superior to bright electroplated chrome in basically every physical category...

Maybe it’s an issue with adhesion if the rod flexes under extreme use?
Even chrome chipping off can be a real problem but I’ve only seen it on hyd rods with super heavy chrome.

 

[nova3930]

Maybe it’s an issue with adhesion if the rod flexes under extreme use?
Even chrome chipping off can be a real problem but I’ve only seen it on hyd rods with super heavy chrome.

I really don't know for sure but I doubt it's that. PVar coatings are only about 5um thick and there's a a molecule scale bond so they don't really chip like thicker electroplated coatings would. Also the primary usage is for machine cutting tools and those have way more flex than people would expect.

I did have a second thought that DLC maybe would be an even better option....

PA Chemical Vapor Deposition | Ionbond

PACVD (Plasma Assisted Chemical Vapor Deposition) is a vacuum based process used to deposit DLC (Diamond Like Carbon) coatings, also known as ADLC (Amorphous Diamond-Like Carbon). All educts of the PACVD process are gaseous.

www.ionbond.com