[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

Re: Acid recovery


I posted 1) to a couple of bulletin boards where the gods of finishing
share their wisdom. As for 2), I would have to agree this is standard, but
there are so many titanium alloys, and so many etch cycles and
preparations, that it leads me to ask what exactly is causing the depletion
of the etch.  For example, some alloy constituents can "poison" this etch
long before titanium is a problem.

Also, you did not say whether this etch is used prior to electroplating.
If so, a wet blast with carefully chosen abrasives may be a viable

Finally, if the etch is not a prep step for plating, what is the goal of
the process?  Perhaps knowing that would lead to another angle.

>I am working with a local aerospace manufacturer who
>uses a mixed Nitric & Hydrofluoric acid bath to etch
>Titanium.  They tell me that this is the "standard" method to
>etch Titanium.  They are presently doing some removal of
>excess Ti to extend bath life - this also leaks some "good"
>acid out.  We are looking for a way to regenerate or
>recover the mixed Nitric & HydroFluoric acid bath.
>1) Does anyone have any experience with this?
>2) Does anyone have a feel for how prevalent the use of
>this mixed acid bath is to etch Titanium?
>     David Westcott
>     Office of Pollution Prevention
>     Connecticut Department of Environmental Protection
>     79 Elm Street - 4th Floor
>     Hartford, CT 06106-5127
>     PHONE:(860)424-3666         FAX:(860)424-4081
>     EMAIL: david.westcott@po.state.ct.us

Terry Foecke
Managing Partner
Materials Productivity LLC (fka Waste Reduction Institute, Inc.)
1821 University Avenue
Suite S-219
St. Paul, MN   55104
(p)  651-603-8282
(f)  651-603-8286