Corrosion

Some months ago (Conservation DistList Instance: 16:42 Friday,
January 10, 2003) I posted an enquiry on the DistList regarding some
unusual 'circular corrosion' forming on iron alloy objects. The
corrosion forms a pattern of concentric circles that appear to
radiate out from central points (visually resembling growth rings in
a tree trunk). The process of testing and analysis is continuing in
order to identify the cause of the 'circular corrosion' which has
formed on various iron alloy objects at the Royal Armouries Museum.
We have been contacted recently by another museum that has
identified similar corrosion patterns on a steel object.

At the Royal Armouries the corrosion has formed on iron alloy
objects with a bright finish and the pitting at the edges of the
circular corrosion is severe causing irreversible damage to the
surface of the objects. As it is now clear that this form of
corrosion is not unique to the Royal Armouries, other museums may
like to consider (time and resources allowing) carrying out a brief
survey to check similar 'bright finish' iron alloy objects in their
collections to ascertain if there are any other similar incidents of
this type of corrosion.

Should anyone require pictures of the corrosion for reference then
please e-mail me.

Many thanks to those who have contacted us about the corrosion
problem, we will keep you informed of any results.


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                  Conservation DistList Instance 17:3
                   Distributed: Friday, June 20, 2003
                        Message Id: cdl-17-3-008
                                  ***