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Ted Mooney, P.E. RET
Pine Beach, NJ
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for Metal Finishing since 1989
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Stripping titanium from stainless steel
Is there a method for stripping a thin layer of titanium from stainless steel? We are using two base metals:304 (not hardened) or
440C hardened to 60-62 Rc. The stainless steel has been lapped to a very fine micro finish which we would like to maintain.
Thank you,
Ken
Plater - St. Paul, Minnesota
May 29, 2010
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If I were a betting man, I would say not very probable. If my boss said try it anyway, I would find some scrap parts and try a 20 parts nitric acid to 1 part HF acid. Possibly 2 parts HF if you are using
50% HF. - Navarre, Florida I don't believe that there is a chemical method that will strip away the titanium without also etching the SS. The usual nitric/HF mix will strip the titanium much faster than it will attack the stainless so, if you are careful about your immersion times, you may be able to get the job done and only have a little bit of polishing time afterwards. I'd suggest that you start with a solution that is about 35% nitric (by volume) and 2% HF (by volume), then establish your removal rates with test pieces of titanium before you try it on a processed part. Careful, this stuff is highly hazardous. Good luck.  Jon Barrows, MSF, EHSSC GOAD Company  Independence, Missouri  |
If the surface you are trying to strip is flat, lap it again, otherwise you can try sand blasting (protect the lapped surface).
Guillermo MarrufoMonterrey, NL, Mexico
June 10, 2010
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Thin layers of titanium can be readily removed using dilute HF. Nitric acid is not required. Thus you can avoid attacking SS. H.R. Prabhakara - ConsultantBangalore Plasmatek - Bangalore Karnataka India Try 5% potassium hydroxide + 5% of 35% grade hydrogen peroxide. This will slowly dissolve titanium and I think not attack stainless.  Jeffrey Holmes, CEF Spartanburg, South Carolina August 4, 2010 Alternatively to Mr. Holmes' suggestion, Sulfuric and/or Nitric acid will work excellently. Titanium forms a reddish-orange coordination complex in acid-peroxide systems. Robert H Kinner- Toledo, Ohio |
H.R. Prabhakara is correct. Titanium has a much higher oxidation potential than the chromium in stainless steel, thus forming a galvanic couple, in which Ti is the sacrificial anode.
Robert H Kinner- Toledo, Ohio
August 4, 2010
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