Carborane–thiol–silver interactions. A comparative study of the molecular protection of silver surfaces

The influence of the constituent elements on the corrosion mechanisms of silver alloys in sulphide environments: the case of sterling silver

“…1 shows this colour variation that goes from light brown (1 and 3 min) to blue (5 and 7 min), blue-grey (15, 30, 60 and 120 min) and grey (240 min onwards). Contrary to what has been suggested, 33 the colours of the corroded Ag surfaces are different from those reported for corroded sterling silver. The latter, under the same conditions, are characterised by a colour variation with different tones of yellow, red, violet, blue and grey.…”

“…The colour of the corroded surfaces depends on the size and shape of the Ag 2 S particles. 33 The oxidation of Ag and Ag 2 S may lead to the formation of silver oxides (AgO and Ag 2 O), but it has also been reported the formation of Ag 2 S over a Ag 2 O lm layer.…”

Tuning the surface potential of Ag surfaces by chemisorption of oppositely-oriented thiolated carborane dipoles

“…Carboranethiols, which represent a class of thiolated inorganic clusters, have been recently introduced in the field on both gold and silver surfaces [11][12][13][14][15]. The stability of their SAMs towards oxidation [11,12], heating [12], and chemical substitution [14] makes them suitable building blocks for self-assembled systems, and good candidates for potential applications in relatively harsh environments containing reactive species. It has been reported previously that no change has been observed in the XP spectra of S2p electrons of the self-assembled monolayers of these molecules on gold substrates after more than a month of their exposure to air at room temperature [12].…”

“…Also heating of these SAMs at 400°C in an ultra-high vacuum does not result in a decrease of boron concentration [12], and it indicates that the molecules are very stable against thermal desorption from the gold surface [12]. Regarding silver surfaces, they were explored mainly for their ability to protect the surface against corrosion [11], and were reported to inhibit corrosion of silver surfaces better than organic thiols of similar dimensions. This experimental evidence is a manifestation of high stability of the carboranethiol-based SAMs.…”

Protecting silver cultural heritage objects with atomic layer deposited corrosion barriers

“…While Ag 2 S is the main component in silver tarnish, sulfate, chloride, oxide, and oxygenated carbon species can also be present [4]. As the Ag 2 S tarnish layer increases in thickness, the initially white color will change to yellow at 10 nm, violet at 26 nm, blue at 47 nm, and finally dark gray [5]. Because silver sulfide tarnish is a surface phenomenon, it does not tend to threaten an object's mechanical integrity.…”