Corrosion

In DistList 15:29 Lisa Young, Conservator, National Air and Space
Museum, inquired about inhibiting copper corrosion products on the
surface of an aluminum alloy containing copper and wondered about a
benzotriazol application or incorporation into a film.

A few years ago we spoke with a technical representative at the
supplier of benzotriazol (BTA) in Cincinnati, Ohio.  This is PMC
Specialties Group 800-543-2466) supplying BTA under the trade name
Cobratec 99. He explained that the inhibitative effects of BTA are
still not completely known except for the knowledge that an
extraordinarily thin and stable corrosion layer is caused to form on
copper preventing further corrosion.  This can only happen, he said,
if the surface of the copper is thoroughly bright (clean).  As for
incorporating BTA in a protective film, the technical representative
pointed out that BTA will volatilize from a film in about two years or
less.  These comments will also interest sculpture conservators who
use Incralac.

Robert Lodge
McKay Lodge Conservation Laboratory, Inc.
Oberlin Ohio


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                  Conservation DistList Instance 15:30
                 Distributed: Tuesday, October 9, 2001
                       Message Id: cdl-15-30-002
                                  ***