Comparative study of patinas formed on statuary alloys by means of electrochemical and surface analysis techniques

Comparative studies of chemical and electrochemical preparation of artificial bronze patinas and their protection by corrosion inhibitor

“…The results have shown that the sulphate patina consists of a smooth structure of cuprite, Cu 2 O, and a crystalline layer of brochantite, Cu 4 SO 4 ·(OH) 6 . The chloride patina consists of smooth structure that is a combination of amorphous Cu 2 O, and SnO 2 , and a crystalline layer of atacamite, Cu 2 Cl(OH) 3 . The electrochemical patina consists of a smooth structure of cuprite, Cu 2 O, and tin-oxide, SnO 2 , and a crystalline layer of malachite, CuCO 3 ·Cu(OH) 2 , and a type of copper-sulphate compound that could not be identified precisely, probably due to its amorphous structure.…”

“…6(1)) has four main features: (a) a low frequency narrow band at 147 cm −1 assigned to OCuO bending modes; (b) an intense band at 516 cm −1 assigned to CuO stretching vibrations; (c) three intense Raman bands at 971, 915 and 825 cm −1 ; and (d) a two bands at 3440 and 3349 cm −1 . This spectrum can be identified as the spectrum of atacamite Cu 2 Cl(OH) 3 [27,31]. The theoretical atomic percents of the atacamite is as follows: 33 at-% Cu, 50 at-% O and 17 at-% Cl, corresponding well to the experimental data.…”

“…The colour depends on the corrosion products formed, which depend partly on the alloy and partly on the environment. Particularly copper or bronzes exposed to urban atmospheres for various decades exhibit a greenish patina, because of the copper carbonate or sulphate crystals, containing several constituents that had been largely studied [2][3][4][5][6][7][8][9][10][11][12][13]. The tone of green is darkened by the presence of copper sulphides or lead and lightened by lead carbonate or tin-oxide.…”

Electrochemical evaluation of patinas formed on nineteenth century bronze bells

“…However, no specific nitrogen compounds were detected in the corrosion products. [17][18][19][20]. However, their absence has also been reported in archaeological cases [6].…”

Raman, X‐Ray Fluorescence Spectroscopies and Graphene Oxide Modified Screen Printed Electrodes to Identify the Pigments and Earth Present in Ancient Leather Samples

“…The knowledge of the chemical composition allows to select treatments/solvents suitable for restoration without interfering with the stability of the pigment and, consequently, with its colour. Moreover, the possibility of monitoring the redox status during time, offers interesting information on the “health status” of the artworks surfaces, containing metallic species , evidencing possible structural modifications.…”