Study On Corrosion Behavior And Laws Of Organic Acidic Pollutants On Copper Materials

Cultural relics are non-renewable.They are important materials for studying ancient history and culture.Among them,copper cultural relics occupy a very important position,and its preservation is seriously threatened by the intrusion of pollutants in the atmosphere and the presence of organic acid gases released by the display cabinets and wooden boards.Based on this,the corrosion behavior of copper materials under the environment of organic acid pollutants is carried out in this paper.The quartz crystal microbalance(QCM)reactivity monitoring instrument is used to investigate the corrosion status of copper and bronze cultural relics under different concentrations of formic acid and acetic acid.The electrochemical impedance spectroscopy(EIS)and Tafel polarization curve(Tafel)are used to explore the micro-electrochemical reaction of the corrosion process in depth.The morphology and composition of the corrosion products are measured by scanning electron microscope(SEM),energy dispersive spectrometer(EDS),and X-ray diffraction(XRD)analysis.The dose-response relationship between metal corrosion rate and pollutant concentration is established.The results show that the corrosion rate of both copper and bronze materials increases with the increase of organic acid concentration.Formic acid is more corrosive to both metals than acetic acid and the corrosion tendency of copper is greater.Changes in temperature and relative humidity in a closed environment affect the formation of liquid films on the metal surface,which in turn interferes with the progress of corrosion reactions.In the formic acid environment,the corrosion products almost completely cover the exposed surface of the metal,while in the acetic acid environment,the corrosion degree of the metal surface is significantly weaker.The final corrosion products of the two metals are cuprous oxide and copper formate crystals or copper acetate hydrates.The metal corrosion rate and the organic acid concentration change in a power function.Based on the functional relationship,the corrosion thickness in the low-concentration organic acid environment is estimated and the pollution degree classification of the organic acid gas concentration in the museum environment is proposed.