Conservation Center, Shanghai Museum, 1118 Longwu Road, Shanghai, 200231, China.
Key Scientific Research Base of Museum Environment, State Administration of Cultural Heritage, 1118 Longwu Road, Shanghai, 200231, China.
Environ Sci Pollut Res Int. 2018 Dec;25(35):35109-35129. doi: 10.1007/s11356-018-3436-6. Epub 2018 Oct 16.
Storing and exhibiting cultural heritages are the basic social functions of museum. Since it is impossible to store or display objects without using containers, cases, or holders, the equipment quality is of great importance. Evaluating the suitability of the equipment should not only learn the mechanical behavior but also focus on the materials because some of them (such as woods) may do harm to the objects due to contaminants released. A convenient test by the deposited metal film method has been proposed previously in order to evaluate more potential museum materials in limited time. The conformance between this method and the Oddy test, the classic method for evaluating and selecting museum materials, is mainly studied in this work. The two testing systems were compared from several aspects such as sample appearance, corrosion product, surface morphology, and metallic content by naked eye and modern characterization measures like X-ray diffraction, scanning electron microscopy, and energy-dispersive spectroscopy. The corrosion mechanisms were deduced according to the corrosion products, including Cu → CuO → CuO and Cu → CuO → Cu(OH)·HO → Cu(HCOO)(OH). The suitability of potential materials for the conservation of metal objects was defined according to the metallic contents of coupons (calculated by atomic ratio) which were classified by the Oddy test. The critical values distinguishing permanently usable from temporarily usable are approximately determined as 70% for copper and 75% for silver, and those distinguishing temporarily usable from unusable are approximately determined as 55% for copper and 60% for silver. The corresponding metal films were classified based on the metallic content standard derived, and then typical appearances of the films assigned to different suitability levels were suggested. Special phenomena, such as the failure in detecting some corrosion products, is attributed to low yield and uneven distribution of ultrafine corrosion products on the films, the covering effect caused by other corrosion products on the copper coupons, and the weakening effect resulted from intensive metal peaks, while some unexpected corrosion conditions on the coupons and the films, are related to the characteristics of general corrosion and pitting corrosion. The results indicate the potential application of the deposited metal film method, giving an optional choice to evaluate and select museum materials with less time. The evaluation methods were preliminarily established from three aspects, such as artificial judgment, metallic content analysis, and corrosion product identification. The artificial judgment is generally applicable, and the other two are useful for verifying the result if possible. More actual cases and further calibration work are essential for further development of the deposited metal film method.
储存和展示文化遗产是博物馆的基本社会功能。由于在不使用容器、外壳或支架的情况下无法存储或展示物品，因此设备质量非常重要。评估设备的适用性不仅要了解其机械性能，还要关注材料，因为其中一些（如木材）可能会因释放出的污染物而对物品造成损害。为了在有限的时间内评估更多潜在的博物馆材料，之前提出了一种通过沉积金属膜方法进行的便捷测试。本工作主要研究了该方法与经典的博物馆材料评估和选择方法——Oddy 测试之间的一致性。从肉眼和现代特征化措施（如 X 射线衍射、扫描电子显微镜和能量色散光谱）等方面比较了这两种测试系统，包括样品外观、腐蚀产物、表面形貌和金属含量。根据腐蚀产物（包括 Cu → CuO → CuO 和 Cu → CuO → Cu(OH)·HO → Cu(HCOO)(OH)）推导出腐蚀机制。根据 Oddy 测试对金属含量（通过原子比计算）进行分类，定义了潜在材料对金属物体保护的适用性。将区分永久可用和暂时可用的临界值大致确定为铜约 70%，银约 75%，将区分暂时可用和不可用的临界值大致确定为铜约 55%，银约 60%。根据得出的金属含量标准对相应的金属膜进行分类，然后提出了不同适用性水平的典型膜外观。对于一些特殊现象，如未能检测到某些腐蚀产物，归因于膜上超细腐蚀产物的产量低且分布不均匀、铜试片上其他腐蚀产物的覆盖效应以及由于金属峰密集而导致的弱化效应，而试片和膜上一些意想不到的腐蚀情况则与一般腐蚀和点蚀的特性有关。结果表明，沉积金属膜法具有潜在的应用前景，为在更短的时间内评估和选择博物馆材料提供了一种可选方案。从人工判断、金属含量分析和腐蚀产物鉴定三个方面初步建立了评价方法。人工判断通常适用，在可能的情况下，后两种方法对于验证结果很有用。进一步发展沉积金属膜法需要更多实际案例和进一步的校准工作。
