Corrosion Products Formed on Silver After a One-Month Exposure to Urban Atmospheres

Abstract

Silver plates were exposed to an urban atmosphere for one month to investigate the corrosion products formed in the early stages. After the exposure experiments, the corrosion products on the silver plates were characterized using x-ray techniques, including x-ray diffraction (XRD) and x-ray fl uorescence analysis (XRF). The XRD patterns of the corrosion products on silver revealed that both silver chloride (AgCl) and silver sulfi de (Ag 2 S) formed. The diffraction peaks originating from AgCl were much stronger than those of Ag 2 S; therefore, AgCl was predominant in the corrosion products observed on the outdoor-exposed silver. The chlorine that formed the AgCl originated primarily from sea-salt aerosols. The seasonal differences in the AgCl intensities in the XRD pattern could be observed. However, there was almost no difference in the Ag 2 S intensities. This was due to the low sea-salt concentrations and relative humidity during winter. Only Ag 2 S formed on the indoor-exposed silver. The absence of AgCl peaks in the XRD patterns indicated that the sea-salt concentrations were quite low in the indoor exposure site. Silver was found to be sensitive to the chloride in sea-salt aerosol and reduced sulfurous gases.KEY WORDS: atmospheric corrosion, silver, urban atmosphere, x-ray diffraction, x-ray fl uorescence analysis

Corrosion of RoHS-Compliant Surface Finishes in Corrosive Mixed Flowing Gas Environments

“…Based on literature survey and extensive internal testing within Alcatel-Lucent, both in the field and in controlled laboratory environments, [9][10][11][12][13][14][15][16][17][18] the parameters of the MFG test were chosen to simulate the worst field conditions which can be encountered in Asia, the Middle East, and Eastern Europe. The test conditions represent Battelle class IV and ISA class G2 and are summarized in Table II.…”

Review of nanomaterial aging and transformations through the life cycle of nano-enhanced products

“…Formation of Ag 2 S is the most common corrosion product in indoor air (McMahon et al, 2005a) while strong oxidants, such as NO x and ozone, can accelerate Ag 2 S formation significantly (Rice et al, 1981;Kim, 2003;Volpe and Peterson, 1989). Alternatively, transformation of Ag to AgCl is usually more dominant in outdoor environments, where environmental components including ozone, UV light and humidity can accelerate atmospheric corrosion (Lin and Frankel, 2013;Watanabe et al, 2006). Humidity and sweat may also promote the generation of secondary NPs.…”

Analysis of Ag Corrosion Products

“…Previous research shows that AgCl and Ag 2 S are the two most common corrosion products in the field, with AgCl usually dominating [14][15][16] except near a volcano with high emission of H 2 S where Ag 2 S is dominant.…”

“…Previous research shows that AgCl and Ag 2 S are the two most common corrosion products in the field, with AgCl usually dominating [14][15][16] except near a volcano with high emission of H 2 S where Ag 2 S is dominant. 17 This might result from a higher deposition rate of chloride outdoors and is different than indoor exposure of Ag where Ag 2 S is more dominant than AgCl.…”

“…Some interesting and maybe unique aspects of Ag outdoor corrosion have been reported. However, the details of how Ag corrodes in the field are not yet clear.Previous research shows that AgCl and Ag 2 S are the two most common corrosion products in the field, with AgCl usually dominating [14][15][16] except near a volcano with high emission of H 2 S where Ag 2 S is dominant.17 This might result from a higher deposition rate of chloride outdoors and is different than indoor exposure of Ag where Ag 2 S is more dominant than AgCl.12 Surprisingly, no AgCl was observed on the surface of Ag after exposure in an ASTM B117 salt spray chamber.14 One reason for studying the corrosion behavior of Ag is to clarify this discrepancy in behavior between field exposure and a supposedly accelerated laboratory test. Enhancing the understanding of Ag might help to clarify why the behavior of other metals and alloys can be different in field exposures and lab tests.…”