Citric vs. Nitric passivation for titanium human implant

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I am a manufacturer of medical implants and instruments. Our customer would like us to use citric passivation as opposed to nitric. From my research I find it to be a better way of passivating, but can't find the certifacation or spec to back it up. I have found a967 to allow for citric passivation of stainless, but not titanium. Anyone out there using citric passivation to passivate titanium implant? If so, what spec are you using?

Steven J. Hicks
medical manufacturer - Springfield, Massachusetts

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Why do you need to passivate titanium anyway?
Ti implant are usually used without passivation.

Marc Teebs
- Montreal, Quebec, Canada

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Passivation occurs naturally on titanium when exposed to and oxygen atmosphere. This layer of oxide can be enhanced through the passivation methods discussed in astm A967 [link is to spec at TechStreet], or possibly A380 [link is to spec at TechStreet] as for stainless steels, using this spec should be ok. Anodizing titanium will drastically improve the alloys ability to oxide rather than just pickling.
Good luck!

Jeff Swayze
- Kelowna, B.C., Canada