Scientific insights of electrochemical replacement approach to describe the origin of Pre-Columbian Peruvian gilded copper-based objects

Abstract

Pre-Columbian Peruvian goldsmiths developed gilded copper-based objects by ancient techniques that require identification to propose conservation strategies. Lechtman H, conducted experiments to suggest that the electrochemical replacement was the gilding technique used by the Moche and Vicus cultural groups. Despite her remarkable achievement, the quantitative data provided by her is still open to discussion. This work focused on obtaining experimental data to recreate her protocol by introducing less gold precursor. Polished copper pieces were plated with an adherent gold film of up to 7.5 µm after immersing them into an electrolytic solution for 3 min and 6 min at 80 °C. Our results demonstrated that the electrochemical replacement technique gives rise to anodic regions in the plated objects. Further studies around the corrosion process that undergoes these heritage objects in burial and environmental conditions are suggested to determine their deterioration rate. Moreover, electroless and galvanic techniques should be explored in order to improve current approaches.