Recommend a Finish for AISI 1095 Carbon Steel

A. As far as I know, there's nothing inside a 1095 carbon steel that could render it passive. It will always be reactive and thus subject to corrosion and oxidation. You have to add something on top of it, be it paint, a protective metal or alloy (either sacrificial or isolating), a stable oxide, nitride or intermetallic compound, an imposed galvanic current or a combination of these. Maybe someone else will differ and enlighten us.

A. You might try heating it up and dunking it in vegetable oil or linseed oil [affil links], and reheating to a lower temp.

A. Hi Dave. Phosphatizing is a conversion coating with zinc or manganese phosphate or similar coatings, usually designed either as a pretreatment for painting or as an oil-holding surface for machined parts. I don't think it's usually used under Parylene coatings, but I think it could be.

Black oxiding and bluing are actually about the same thing, a controlled oxidation of the surface of steel to a depth of only a few millionths of an inch. It's done more for appearance than corrosion resistance and requires waxing or oiling to deter rusting.

I think your situation will be that these processes can be done but will impart little corrosion resistance if oiled and essentially none if not.

One thing that might help is nitriding, whether it be salt bath nitriding, gaseous, or plasma. You might look into the QPQ (quench-polish-quench) process. I am not sure if AISI 1095 is a good candidate steel for QPQ, but I'm sure the vendors of the process could tell you in an instant. Good luck.

Regards,