Work

Multilayer design of sustainable multifunctional Zr–Cu–N coatings: A route for enhanced mechanical and antibacterial performance

Year: 2025

Type: article

Abstract: Wear-resistant protective coatings with antimicrobial activity are essential for enhancing durability and hygiene in various settings, including healthcare facilities, public spaces, the food industry, consumer products, and industrial environments, by preventing pathogen spread and ensuring long-term use under frequent contact and cleaning. In this study, we developed sustainable multifunctional Zr-Cu-N coatings with exceptional hardness, damage tolerance, and antibacterial properties using non-reactive and reactive sputtering of only two elemental Zr and Cu targets without external heating. The superior performance of these coatings stems from a sophisticated multilayer architecture combining elastic ZrCu metallic glass, hard and stiff ZrN ceramic, and hard and tough ZrN-Cu nanocomposite coatings. Each constituent was optimized for elemental and phase composition, as well as mechanical properties, before being integrated into multilayer structures to improve damage tolerance and incorporate antibacterial functionality. The antibacterial efficacy was tested in a real high-traffic environment over a 60-day period, consistently demonstrating effective antimicrobial performance. Fracture stress and fracture toughness were assessed through in situ bending experiments on microcantilever beams fabricated by focused ion beam milling. The results revealed that optimizing the thicknesses of both ductile and stiff sublayers in the multilayer coatings significantly enhances damage tolerance while maintaining high hardness and wear resistance. The incorporation of Cu in an unbonded state within the ZrN-Cu nanocomposite facilitates the sustainable and scalable production of these multifunctional protective coatings with antibacterial properties, making them ideal for large surface applications in high-traffic environments such as hospitals, office buildings, public transport, and other public spaces.

Source: Materials & Design

DOI: 10.1016/j.matdes.2025.114037