Stainless steel sculpture and salt water

Dennis A. Baltuskonis <dbaltusk [at] trinity__edu> writes

>Texas Gulf coast city is having a recurring problem with a large
>"stainless steel" sculpture installation and would like to hear of
>extended actions to take toward maintaining the pieces.  The artist
>allegedly used an "inferior" grade of stainless steel, which does
>exhibit signs of rust within a year of each "cleaning".  The
>sculpture piece is located directly across from the sea wall and is
>therefore exposed year round to the gulf coastal salt water
>environment. ...

Stainless steels are very susceptible to corrosion in a marine
environment. It is the passive layer of Cr-O on the stainless steel
that gives it its corrosion resistance, but this is disrupted by
chlorides.  Regular washing with fresh water will help but short of
moving or sheltering the sculpture in some way it will continue to
corrode.  Coating the sculpture will actually cause it to corrode
more rapidly.  The passive layer requires the presence of oxygen to
work, otherwise stainless steels will behave like iron and pitting
corrosion will occur.  You may notice this phenomena along weld
lines.

I did some research into stainless steels a couple of years ago and
found it difficult to find much in the conservation literature.
There were a few useful web sites on stainless steels though.

Vanessa Roth
Objects Conservator
Art Gallery of Western Australia


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                  Conservation DistList Instance 18:10
                 Distributed: Thursday, August 5, 2004
                       Message Id: cdl-18-10-003
                                  ***