Investigation into the surface structural coloration of Ti6Al4V alloys for use in the anti-counterfeiting of critical industrial products

Abstract Nowadays, procurement strategies for complex products rely on a global supply chain dimension. This practice exposes companies to increasing risks of counterfeiting and loss of control across the supply chain, with significant implications for safety, reliability, reputation, and competitiveness. Conventional anti-counterfeiting strategies exhibit clear limitations, as the trade-off between cost-effectiveness and authentication reliability often compromises product uniqueness and integrity. In this context, plasmonic technology represents a promising approach among the surfaces’ functionalization techniques: by harnessing nanoscale electronic oscillations, metallic substrates can be endowed with an optical “fingerprint” that is unique, irreproducible, and capable of verifying product provenance. Here, we present an experimental study on Ti-6Al-4 V alloy samples, using sputtering deposition to incorporate thin ITO films and silver nano-islands. Optical and morphological characterizations via ellipsometry, reflectance spectroscopy, and atomic force microscopy reveal that plasmonic surfaces can precisely modulate color and reflectance, generating a proper optical marker. The process yields a macroscopically reproducible color, which offers a high (but not extreme) level of security, as well as a unique microscopic pattern that, however, requires atomic force microscopy (AFM) to be read. This case study underscores the potential of plasmonic technology for high-value sectors, providing an initial practical result for enhancing product security, authentication, and traceability.