The conservation of archaeological pieces is a stage, sometimes essential, in the study of objects protected in historical sites. When in addition to natural agents such as water, air and temperature, there is the presence of atmospheric pollutants, the degradation processes are accelerated to such a degree that the total loss of a historical vestige can be had. These agents induce even deterioration in metal parts through aggressive corrosion processes.

The evaluation of the patinas by means of electrochemical techniques in the copper-based metallic materials of the historical heritage will allow to acquire knowledge about the formation of the corrosion products and the protective coating that the superficial film provides to the material. In this work, sulphate patina are synthesized by using an aqueous solution of copper sulphate, chloride patina using an aqueous solution of ammonium chloride and electrochemical patinas immersed in a sulphate / carbonate solution. The morphological and structural characterization of each of the patinas was carried out through scanning electron microscopy, X-ray and Raman energy dispersion spectrometry.

The main characteristic of the patinas formed is the blue-green coloration, since it facilitates the identification of corrosion products such as brochantite, in sulphate patinas, atacamita in the chloride patinas and malachite in the electrochemical patinas. In analysis by means of electrochemical techniques and having variations of contaminants in the test medium indicate that the best behavior for protection against corrosion is presented by the patina formed with sulphates.