腐蚀过程中青铜析出还原铜晶粒的机理

Mechanism of formation process of pure Cu crystals in bronze corrosion

采用循环伏安法(CV)研究了青铜在模拟土壤介质中的电化学行为。对循环伏安谱中氧化过程及还原峰电位下的腐蚀产物进行了X射线衍射检测。结果表明,氧化过程为生成有害锈(CuCl)的反应,还原过程为CuCl还原成纯铜的反应。用金相显微镜、扫描电子显微镜(SEM)和原子力显微镜(AFM)研究了纯铜晶粒及腐蚀界面的形貌特征,在实验室条件下模拟了纯铜晶粒在青铜文物表面的析出过程,通过延长还原时间CuCl可全部被还原成纯铜,其生成条件在土壤中也具备,这为除去青铜文物上的有害锈(CuCl)提供了理论和实验依据。

The cycle voltammetry(CV) technique was used to study the electrochemical behaviour of bronze in simulated edaphic electrolyte. Analyzing the composition of corrosion products formatted during oxidation process and at reduction peak with XRD, the results show that the oxidation process is the formation process of harmful patina CuCl and the reduction process is the reaction of CuCl reduced or deoxidised to pure Cu. The metallographic microscopy, SEM and the atomic force microscopy(AFM) were used to observe the morphological characteristics of pure Cu crystals and the corrosion interface. The formation process of pure Cu on bronze archaeology is simulated in laboratory conditions, in which CuCl can be fully deoxidised to pure Cu for extended period of time. The same condition for the formation of pure Cu can also be provided in soil. This outcome forms the theoretical and experimental basis for restoring excavated bronze artefact from harmful patina CuCl.