Analysis of the kinetic growth of an electrochemically formed bronze patina using the layer-pore resistance model

The growth of patinas on artistic or archeological copper alloys is a determining stage to reproduce similar surface conditions such as corrosion protection of cultural heritage materials. In this work, the kinetic growth and protective properties of the corrosion products layer of a quaternary copper alloy have been characterized using linear sweep voltammetry (LSV), electrochemical impedance spectroscopy (EIS), scanning electron microscopy-EDS, atomic force microscopy, X-ray diffraction, and Raman spectroscopy. The results of LSV show that the patina formation is a mixed process consisting of dissolution and direct film formation. EIS results show that the kinetic formation modifies the characteristics of the corrosion layer allowing a Warburg-like diffusive mechanism or the response of a porous oxide layer without diffusive phenomena. The roughness and thickness of the patina enhance with the decrease in the scan rate. The patina is mainly composed of copper and tin corrosion products.

Automated summary

This study characterized the kinetic growth and protective properties of the corrosion products layer of a quaternary copper alloy using various techniques. The results revealed that the formation of patinas on the alloy is a mixed process involving dissolution and direct film formation. The characteristics of the corrosion layer were modified by the kinetic formation, resulting in a Warburg-like diffusive mechanism or the response of a porous oxide layer without diffusive phenomena.