Double-Layer Silicon Dioxide/Titanium Dioxide Sol-Gel Coating for Wearable Gold Accessories

An investigation evaluated the corrosion resistance behavior of a silicon dioxide/titanium dioxide (SiO2/TiO2) sol-gel coating on gold-plated fashion accessories, especially watches. A double layer of SiO2/TiO2 with varied molar concentrations (0.1 to 0.5 M) was applied to gold-plated accessories by a dip-coating process. The coating was characterized using an atomic force microscope, scanning electron microscope, and stylus proflometer. The corrosion behavior was studied by potentiodynamic polarization experiments in an artifcial sweat solution. The coating with 0.3 M SiO2/TiO2 showed better corrosion inhibition compared to other concentrations. The coated layer retained the luster and brilliance of gold over a wide range of concentrations.