Abstract:
The deleterious interaction of some traditional sulphide artists pigments and copper ions results in the formation of black copper
sulphides, in particular, covellite (CuS), and, hence, the discolouration of valuable artworks. In this paper the interaction of
malachite, a source of copper(II) ions, with the pigment cadmium yellow, a sulphide pigment comprising of a solid solution of
cadmium and zinc sulphides, is investigated by XRD and TG-MS. XRD showed the presence of the copper sulphide and cadmium
carbonate phases, produced by a simple ion exchange mechanism. TG-MS showed the complexity of the range of metastable phases
produced. The identification of these phases, however, requires further work.
