Passivation of Iron

I'm doing a research on the passivation of historical iron objects.
If someone has recent information about chemical substances used to
form a stable passive film on the surface of iron objects, please
let me know. If any body has any practical experience in the use of
passivators on iron or can give me any comments about tannins or
phosphoric acid, I will be happy to her from you. I have read some
paper about the subject and some specific substances, but I would
like to get up-dated information. Thanks for your help,

Carolusa Gonzalez Tirado
Conservator
Escuela Nacionar de Conservacion, Restauracion y Museografia
Mexico

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                  Conservation DistList Instance 10:89
                 Distributed: Thursday, April 17, 1997
                       Message Id: cdl-10-89-017
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