Analytic procedure for the evaluation of copper intermetallic diffusion in electroplated gold coatings with energy dispersive X-ray microanalysis

Tailoring barrier layers design for haute couture through X-ray microanalysis: Insights and guidelines

“…To evaluate the intermetallic diffusion the method proposed by Giurlani et al [ 22 ] was employed and D was calculated as described in (4) . …”

“…t s should not be taken as an indication of the formation of a homogeneous layer of diffused species, but as an approximation of the equivalent thickness of the diffused mass having bulk density; this approximation is fundamental for applying the Tompkins mathematical model cited before. The methodologies to determine all the t x (x = s, c) are reported in the 2.2 subsection and extensively discussed in the presenting methodology paper [ 22 ]. In this work, specifically, to evaluate barrier layer performances, it is proposed to divide t c in two terms: the thickness of the barrier system (t b ), and the thickness of the topcoat (t t ), which in this study is the thickness of the gold layer; in the case of AuCu samples t c = t t as t b = 0.…”

“…A common test that is used in the decorative field is based on a colorimetric assay, where a sample is annealed at 180 °C and the colour difference in the CIE L*a*b colour space [ 21 ] is evaluated; this method, albeit inexpensive, is proven to be inaccurate and to give, at least, qualitative results. In a previous work we developed a novel methodology based on Energy Dispersive Spectroscopy (EDS) microanalysis and X-ray fluorescence, that has been able to determine the diffusion coefficients of Au–Cu electroplated systems [ 22 ]. This procedure seems to be the best candidate to be used as a cheaper and effective way to study barrier layers, especially in industrial fields.…”

“…Then, additional evaluations were performed on two systems with Tin–Ruthenium as anticorrosion layer to determine if this alloy acts, also, as a barrier layer. Lastly, measurements on Au–Cu systems varying the deposition parameters and the use of a AuCo alloy layer which has previously exhibited barrier properties [ 22 ].…”

PVD for Decorative Applications: A Review

“…Amorphous carbon obtained via DC magnetron sputtering as a promising barrier layer for Cu diffusion was proposed by An [233] in 2020. A complication in the design of barrier layers is the evaluation methodology, as a standard method of evaluation is lacking: to overcome this limit, in 2023 a novel technique based on X-ray microanalysis suited for the decorative and fashion industries was proposed [234]. The line-of-sight deposition limit is intrinsic to PVD, and with an engineering-like approach (substrate rotation, multi-target systems, and others) it is necessary to bypass that [173].…”