Tarnish resistance of silver by gold microplates coating

Abstract

Abstract Silver is a promising precious metal for the jewelry industry. The silver jewelry findings exposed to air would be tarnished because it comes into contact with sulfur particles in atmospheres. Therefore, surface treatments and coating methods were developed to prevent the tarnishing of silver. However, the methods still have several limitations and disadvantages. The objective of this research was to develop gold microplates for surface coating and tarnish resistance of silver. In this study, the gold microplates were synthesized by chemical reduction methods. Multilayer gold coating was performed by a simple dip coating method to produce the gold film using a gold microplate solution, which disperses gold particles in ethylene glycol. The anti-tarnish properties of the coated silvers were investigated using the sodium sulphide solution. To specify the color change after multilayer coatings of gold particles and tarnishing test, the color measurement was determined according to the Commission Internationale d’ Eclairage (CIELAB) standard by UV-visible spectrometer. The result pointed out that the gold microplates layers coating on silver are invisible and efficiently prevents tarnishing.