Department of Chemistry, Materials and Chemical Engineering "Giulio Natta", Politecnico di Milano, Piazza Leonardo da Vinci 32, 20133, Milan, Italy.
Getty Conservation Institute, 1200 Getty Center Drive, Suite700, Los Angeles, CA, USA.
Environ Sci Pollut Res Int. 2020 Apr;27(12):13081-13094. doi: 10.1007/s11356-020-07814-4. Epub 2020 Feb 3.
The cleaning of metallic artworks is a crucial step for their preservation. Cleaning operations generally aim at removing deposits and corrosion layers, and all the non-stable and potentially reactive phases formed as a consequence of the interaction of the metal with the environment. Thus, all secondary-formed compounds and layers that can undermine the overall preservation of the artwork, both from the esthetic and the corrosion point of view, should be removed. On the other hand, superficial stable patinas contributing to the artistic and historic value of the objects and that may provide protection to the metallic surface should be preserved. The optimal cleaning procedure should be able to promote a long-term improvement of the corrosion resistance of the surfaces. Therefore, the long-term monitoring of the corrosion behavior of the cleaned surfaces with electrochemical techniques could provide valuable information for the selection of the optimal methodology. In this work, five cleaning procedures have been applied to five bronze sculptures. The cleaned surfaces have been characterized following a multi-analytical and non-invasive approach, and the long-term evolution of their corrosion behavior has been monitored by means of on-site non-invasive linear polarization resistance (LPR) and electrochemical impedance spectroscopy (EIS) measurements for more than 2 years.
金属艺术品的清洁是其保存的关键步骤。清洁操作通常旨在去除沉积物和腐蚀层，以及由于金属与环境相互作用而形成的所有非稳定和潜在反应性相。因此，所有可能破坏艺术品整体保存的次生形成的化合物和层，无论是从美学还是腐蚀的角度来看，都应予以去除。另一方面，应该保留有助于物体艺术和历史价值的表面稳定的铜绿，并且可能为金属表面提供保护。最佳的清洁程序应该能够提高表面的耐腐蚀性。因此，采用电化学技术对清洁表面的腐蚀行为进行长期监测，可以为选择最佳方法提供有价值的信息。在这项工作中，五种清洁程序已应用于五个青铜雕塑。清洁后的表面采用多相和非侵入性的方法进行了表征，并通过现场非侵入性线性极化电阻（LPR）和电化学阻抗谱（EIS）测量对其腐蚀行为的长期演变进行了监测，监测时间超过 2 年。
