Method for creating artificial brochantite

I am a Swiss student in conservation from the Haute Ecole d'Arts
Appliques Arc in Switzerland, doing my master at the National
Conservation Centre (National Museums Liverpool).

My research focuses on the interactions between laser light and
copper alloy outdoor monuments.

In order to carry out laser tests, I have to create brochantite on
copper alloy samples.

I have already tried the method proposed by Hayez (Micro-raman
spectroscopy used for the study of corrosion products on copper
alloys: study of the chemical composition of artificial patinas used
for restoration purposes, Analyst(2005)150, 550-556) which consists
in an immersion of 3 weeks in a solution of 6g KClO3, 3g CuSO4.5H2O
and 4g Na2SO4.10H2O in 1L deionised water adjusted to pH3 with
H2SO4.

Some brochantite has formed but the pulverous crystals are very
spread out on the surface and the layer is very uneven. As I need to
get a more even and thicker layer of brochantite, I'd like to find a
complementary method for creating it.

I know that exposure of the samples to high levels of SO2 gases in
chambers would certainly give good results, but it is more
expensive.

Does anyone know another method for creating artificial brochantite,
Or even a place where I could access corrosion tests chamber in the
UK?

Maya Froidevaux


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                  Conservation DistList Instance 20:30
                 Distributed: Friday, December 1, 2006
                       Message Id: cdl-20-30-014
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