Restoration of Original Color Appearance of Decorative Iron-Based Metal Artworks by Laser Treatment

This article is focused on the study of the possibility of the restoration of the lost decorative color appearance of iron-based metal artworks. An ytterbium fiber laser (1064 nm) was used to irradiate carbon steel surfaces. Laser-induced color oxide layers of blue, yellow, brown, and white colors were obtained on the surface of carbon steel by adjusting the main laser radiation parameters: power, repetition rate, beam scanning speed, and pulse duration. In experiments, we used mockups on the surface of which colored oxide layers had been obtained by means of laser treatment. Then we damaged the oxide layers, creating artificial corrosion, and reproduced the original color appearance by means of several stages of laser processing, including cleaning, polishing, and local heating of the mockups' surfaces. The conducted studies show that the application of lasers is a promising method for the reconstruction of the color appearance of iron-based cultural heritage objects.