缓蚀剂对青铜器及其有害锈缓蚀作用机制研究

Our previous researches demonstrated that the formation, evolution and remnant of harmful patina on bronze ware can cause cyclic damage to bronze substrate, the prefilming method which is actually used in protection bronze relics can not effectively restraint harmful patina to corrode bronze further. This project will calculate orbit energies and charges of atoms in inhibitors and copper patina with different valences, forecast combination tendency of electron donors to acceptors and verify it, by quantum computation, frontier orbital theory and EIS experiments, respectively. XPS, ECAFM, EN tests will be used to investigate the combination selectivity of inhibitors to chemical elements and texture of bronze alloy, to different patina areas, to inlayer CuCl. The order and compact degree of inhibition film will be investigated. The inhibition effect of inhibitors to disproportionated reaction of Cu atoms with different valences, hydrolysis reaction and oxidation reaction of CuCl process will be explored. In view of different mechanism of inhibitors and Cu(0),Cu(Ⅰ),Cu(Ⅱ） atoms coexist on bronze ware, with quantum computation results, design synergistic inhibition film which is suitable to self-assemble on bronze ware in molecular level, set up assembling model. The stability and durability of inhibiting film in environment media will be analyzed by M-S cures, salt tests,numerical analysis etc. The mechanism of synergistic inhibitors in protecting bronze substrate and its harmful patina will be proposed and discussed. These achievements can provide theoretical foundation for protecting bronze relics with patina.

申请人前期研究发现青铜器有害锈的生成、演变及残留，会对青铜基体产生循环破坏，青铜器的预膜法缓蚀过程不能有效阻止有害锈的危害。本项目采用量子化学计算缓蚀剂、各价态锈的轨道能、原子电荷，用前线轨道理论判断电子授-受体的结合倾向，通过试验验证计算结果；用x-射线光电子能谱、原位电化学原子力显微镜等研究缓蚀剂与青铜基体的组成、结构，锈蚀分布不均区域，内层CuCl等结合的选择性和缓蚀膜的有序、致密性；研究缓蚀剂阻止CuCl的演变反应，不同价态铜间的歧化反应的机理；基于缓蚀剂不同作用机制及青铜器上Cu（0）、Cu（Ⅰ）、Cu（Ⅱ）原子共存，从分子水平优化设计适用于在青铜器表面自组装的协同缓蚀膜并建立组装模型，用M-S曲线、盐雾试验法等研究环境因素对缓蚀膜的稳定性和耐久性的影响，揭示缓蚀剂（预膜法缓蚀过程）协同稳定青铜器及其有害锈的原理，为带锈青铜文物的保护提供理论基础。

青铜器有害锈的生成、演变及残留，会对青铜基体产生循环破坏，青铜器的预膜法缓蚀过程不能有效阻止有害锈的危害。本项目研究了青铜表面常见腐蚀产物之间的转化条件及腐蚀产物转化过程对青铜腐蚀过程的促进或保护作用；筛选了对表面带CuCl锈具有优异缓蚀效果的L-半胱氨酸有机缓蚀剂和对表面带Cu2(OH)3Cl锈青铜腐蚀过程具有显著抑制作用的硫酸亚铈稀土缓蚀剂。基于以上结果，本项目通过量子化学计算及分子动力学模拟计算研究了有机缓蚀剂分子与青铜表面不同锈蚀产物的相互作用机制，并通过电化学噪声结合表面形貌图像处理分析方法分析了青铜不同表面状态对青铜腐蚀过程及缓蚀剂缓蚀作用机制的影响。项目研究过程中，申请人发现可见光及紫外光对表面带半导体类锈蚀产物青铜的腐蚀过程具有明显促进/抑制作用，并对这一促进/抑制作用产生的机理进行了初步研究。综合上述结果，本研究揭示了缓蚀剂稳定青铜器及其有害锈的原理，为带锈青铜文物的保护提供了理论基础。