A new standards-based scanning electron microscopy with the energy-dispersive X-ray spectrometry (SEM–EDS) quantification method was used to analyze the thin-film coating of an 18th century French textile decorated with metal threads in variable pressure conditions. This analytical technique can allow for nondestructive quantitative characterization of the near surface of cultural heritage objects small enough to be placed in an SEM chamber that may contain corrosion products, without applying a conductive coating. A multivoltage analysis consisting of measurements taken at a series of electron beam energies was obtained and input into a film thickness and composition (FTC) computational model to characterize a layered Au on Ag reference material, in addition to a historic metal thread. Using the FTC computation, the thread coating was determined to be an alloy ≈ 80% Au 20% Ag on a nominally pure Ag substrate, and this composition matches a minimum gold standard allowed for goods around the time of manufacture. The computed gilding thicknesses range from single digit nm to 300 nm depending upon surface inhomogeneities formed during the production of the thread. Interaction volumes and X-ray spectra generated by Monte Carlo modeling are consistent with the measured gilding thicknesses and compositions. Validation of the FTC-computed gilding composition and thickness variations were obtained by cross-sectional analysis.

中文翻译：

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对历史悠久的金属螺纹上的薄膜涂层进行无损显微分析

一种新的基于标准的扫描电子显微镜和能量色散 X 射线光谱 (SEM-EDS) 量化方法用于分析 18 世纪法国纺织品在可变压力条件下装饰有金属线的薄膜涂层。这种分析技术可以对足够小的文化遗产物体的近表面进行无损定量表征，这些物体小到可以放置在可能包含腐蚀产物的 SEM 室中，而无需施加导电涂层。获得了由在一系列电子束能量下进行的测量组成的多电压分析，并将其输入到薄膜厚度和成分 (FTC) 计算模型中，以表征 Ag 参考材料上的分层 Au，以及历史悠久的金属线。使用 FTC 计算，螺纹涂层被确定为在名义上纯银基材上的合金 ≈ 80% Au 20% Ag，并且该成分与制造时允许的商品的最低黄金标准相匹配。计算出的镀金厚度范围从个位数纳米到 300 纳米，具体取决于线生产过程中形成的表面不均匀性。Monte Carlo 模型生成的相互作用体积和 X 射线光谱与测得的镀金厚度和成分一致。FTC 计算的镀金成分和厚度变化的验证通过横截面分析获得。计算出的镀金厚度范围从个位数纳米到 300 纳米，具体取决于线生产过程中形成的表面不均匀性。Monte Carlo 模型生成的相互作用体积和 X 射线光谱与测得的镀金厚度和成分一致。FTC 计算的镀金成分和厚度变化的验证通过横截面分析获得。计算出的镀金厚度范围从个位数纳米到 300 纳米，具体取决于线生产过程中形成的表面不均匀性。Monte Carlo 模型生成的相互作用体积和 X 射线光谱与测得的镀金厚度和成分一致。FTC 计算的镀金成分和厚度变化的验证通过横截面分析获得。