The jewelry manufacturing industry has carried out much research to remedy the effects of tarnishing on silver. With the common knowledge that hydrogen sulfide (H2S) causes tarnishing, the industry has focused on two widely used tests for tarnish identification: the dipping test and the fuming test. However, these tests have not been standardized; for example, there are different recipes for the chemicals used and varying amounts for the H2S concentration. But do these two tests resemble real-world circumstances? Similar to the secondary ion mass spectrometry (SIMS) test, x-ray photoelectron spectroscopy (XPS) is a technique that can be employed on silver rings of different compositions and worn by a sample size population of wearers with different daily lifestyle circumstances to better represent real-world conditions. Potentiodynamic tests were conducted to mimic various real-world solutions: hanks solution (simulated body fluid), artificial sweat, sulfur-containing liquid, etc. The polarization voltage sweep was employed to monitor the exchange of electrons through silver articles. All test results were then compared to identify the mounting complexity of the tarnishing problem.

Author: Dr. Boonrat Lohwongwatanai