Insights into electrolytic stabilization with weak polarization as treatment for archaeological copper objects.
Immersion of corroded copper artefacts in dilute sodium sesquicarbonate solution is a well-recognized stabilization technique--especially in the conservation of objects recovered from marine environments and therefore saturated with chlorides. Here we describe three linked experiments performed to investigate a variation on this treatment, involving the application of a low potential to the artefact in order to drive the chloride extraction process. This includes a new spectroelectrochemical approach which allows 2-D pseudorandom X-ray reflection diffraction patterns to be obtained without interrupting the reaction in solution. Experiments were carried out on synthetically produced chloride layers on copper (nantokite and atacamite). We show that a thick chloride layer is, in general, replaced by a thin cuprite layer through a mechanism which involves detachment of the chloride crystallites from the surface prior to dissolution.
Adriaens
Annemie
A
Department of Analytical Chemistry, Ghent University, 9000, Ghent, Belgium. annemie.adriaens@ugent.be
Dowsett
Mark
M
Leyssens
Karen
K
Van Gasse
Bjorn
B