The Characterization of a New Pale Blue Corrosion Product Found on Copper Alloy Artifacts

AbstractA new pale blue corrosion product has been found on copper alloy artifacts in the collections of a number of institutions. The corrosion product has been characterized using X-ray powder diffraction, X-ray photoelectron spectroscopy, wavelength X-ray dispersive spectroscopy and Raman microspectroscopy. The corrosion product is a copper(II) compound, containing copper and sodium in a ratio of approximately 1:1 along with formate and acetate groups. It is speculated that formic (methanoic) and acetic (ethanoic) acid vapors arising from materials used to house the objects contribute to the formation of this compound.