ABSTRACT

The appearance of silver objects deteriorates due to the formation of a brown-to-black tarnish layer. Several methods are available for removing these tarnished layers, ranging from polishing through chemical cleaning to electrochemical methods. This study presents a low-cost and low-toxicity method that uses sodium glycinate to clean silver. Cleaning tests were performed on both artificially tarnished prototypes and naturally tarnished objects after characterizing them; scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDX) were used to characterize the artificially tarnished prototypes, and X-ray fluorescence (XRF) was used to characterize the naturally tarnished objects. The aggressiveness of the baths was analyzed by measuring the leached amount obtained through atomic absorption spectroscopy (AAS) and SEM. The procedures used for cleaning the artificially tarnished prototypes served as a guide for cleaning two naturally tarnished objects: a halo and a crown. Cleaning was guided by the presented method’s characteristics as well as the object’s unique characteristics and condition.

摘要

由于形成棕黑色变色层，银色物体的外观会变差。有多种方法可用于去除这些失去光泽的层，从抛光到化学清洁再到电化学方法。本研究提出了一种使用甘氨酸钠清洁银的低成本、低毒性方法。对人工失去光泽的原型和在表征后自然失去光泽的物体进行清洁测试；扫描电子显微镜 (SEM) 和能量色散光谱 (EDX) 用于表征人工失去光泽的原型，并使用 X 射线荧光 (XRF) 表征自然失去光泽的物体。通过测量通过原子吸收光谱 (AAS) 和 SEM 获得的浸出量来分析浴的侵蚀性。用于清洁人工失去光泽的原型的程序可作为清洁两个自然失去光泽的物体的指南：光环和皇冠。清洁是由所提出的方法的特征以及对象的独特特征和条件引导的。