CHARACTERIZATION OF CORROSION PRODUCTS ON CHALCOGRAPHIC COPPER PLATESAFTER 200 YEARS EXPOSURE TO INDOOR ATMOSPHERES

This work studies the characterization of corrosion products formed on six eighteenth century chalcographic copper plates preserved in the N ational Chalcography Collection in the San Fernando Royal Academy of F ine Arts in Madrid.The experimental methods used were X-ray diffractio n analysis (XRDA), Infrared spectroscopy (IRS), Auger electron spectro scopy (AES) and X-ray photoelectron spectroscopy (XPS). The main compo unds found were malachite CuCO3 . Cu(OH)2, atacamite CuCl2.3Cu(OH)2, n antokite CuCl, tenorite CuO, and cuprite Cu2O. Cuprite is the main com pound found on the smooth areas of chalcographic plates, forming tarni sh films. The thickness of the tamish films is approximately 10-15 ang strom.