Results about the efficiency of the laser cleaning on the reduction of corrosion products from the surface of ancient coins are reported. In this work an ancient copper coin datable from 1500 to 1600 A.D. and a UV excimer laser were utilized. The goal of this work consists to study the potentiality of UV laser treatment in the reduction of the chlorine concentration on the coin surface which is the main responsible of the corrosion processes of the ancient coins. We used Energy Dispersive X-Ray Fluorescence (EDXRF) and X-Ray Diffraction (XRD) techniques to estimate the chemical composition of the coin surface, before and after UV excimer laser cleaning. In particular, we measured the chlorine, copper and calcium concentrations. We found that a radiation dose of about 19 J/cm2 was able to reduce the chlorine concentration from 2.3 % w/w to 0.6 % w/w without damaging the metal bulk.
Selective Laser Cleaning of Chlorine on Ancient Coins
BUCCOLIERI, ALESSANDRO;BUCCOLIERI, Giovanni;CASTELLANO, Alfredo;DI GIULIO, Massimo;LEO, LAURA SANDRA;LORUSSO, ANTONELLA;NASSISI, Vincenzo;
2007-01-01
Abstract
Results about the efficiency of the laser cleaning on the reduction of corrosion products from the surface of ancient coins are reported. In this work an ancient copper coin datable from 1500 to 1600 A.D. and a UV excimer laser were utilized. The goal of this work consists to study the potentiality of UV laser treatment in the reduction of the chlorine concentration on the coin surface which is the main responsible of the corrosion processes of the ancient coins. We used Energy Dispersive X-Ray Fluorescence (EDXRF) and X-Ray Diffraction (XRD) techniques to estimate the chemical composition of the coin surface, before and after UV excimer laser cleaning. In particular, we measured the chlorine, copper and calcium concentrations. We found that a radiation dose of about 19 J/cm2 was able to reduce the chlorine concentration from 2.3 % w/w to 0.6 % w/w without damaging the metal bulk.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
