Corrosion Behavior Of Typical Organic Acid Pollutants And Its Composite Environmental Factors On Bronze Materials

Bronze artifacts have become the common wealth of mankind for its high artistic value and humanistic value.It can provide an important reference for us to study the development of ancient culture and art.However,as the research progressed,we began to notice that the organic acid gas in the atmosphere would pose a huge corrosion threat to the preservation of bronze artifacts,and such corrosion threats are often overlooked.Besides that,environmental factors such as temperature and humidity also have different influence on bronze artifacts.Therefore,it's very important to research the corrosion behavior of organic acid gas and its environmental composite factors on bronze materials for the preservation and protection of bronze artifacts.In this paper,three methods were used,including the thin electrolyte layers(TEL)experiment,quartz crystal microbalance(QCM)experiment and simulated exposure environment accelerated experiment.Electrochemical impedance spectroscopy(EIS)and potentiodynamic polarization curves(Tafel)were used to investigate the electrochemical corrosion behavior of bronze samples.Scanning electron microscopy(SEM),energy dispersive spectroscopy(EDS)and X-ray diffractometry(XRD)were used to characterize and analyze the morphology and composition of the corrosion products on the surface of bronze samples.The corrosion behavior and mechanism of bronze materials were inferred by analyzing and comparing the experimental results under various environmental conditions.The results show that the corrosion resistance of bronze sample in the corrosion solution of containing organic acid is significantly lower than that not containing organic acid,indicating that the corrosion rate will be accelerated when organic acid is present in the environment.When the thickness of the thin electrolyte layer is about 100?m,the corrosion reaction rate of the bronze sample is the fastest,and the thickness at this time is called the critical thickness.In addition,the corrosion rate of the bronze sample in formic acid is significantly greater than that in acetic acid,which is speculating due to the dissociation coefficient of formic acid is greater than that of acetic acid.In the corrosion experiment of organic acid combined with relative humidity on bronze,the corrosion rate of the bronze material increases as the relative humidity increases.However,it can be seen from the experiment results that there is a critical humidity value in the corrosion reaction.When the ambient humidity exceeds the critical humidity value,the corrosion reaction will show a sudden acceleration.And the critical humidity value in this experiment is about 70%.In the corrosion experiment of organic acid combined with temperature on bronze,the corrosion rate of the bronze material increases as the temperature increases.However,it can be inferred from the experiment phenomenon that there is a transition temperature in the corrosion reaction.When the ambient temperature exceeds this value,the reaction rate will start to slow down or even stop.By carrying the simulated exposure experiment,it can be seen that the corrosion products on the surface of the bronze sample have different morphologies and compositions under different environmental conditions.In addition,the results show that the final corrosion products of the bronze samples in the formic acid environment and acetic acid environment are respectively Cu2O and copper carboxylate hydrate.