Development and characterization of a multilayer silver/silver-tantalum oxide thin film coating on stainless steel for biomedical applications

Stainless steel 316L (SS 316L) is widely used in biomedical applications, particularly in surgical tools. Although this class of material has good wear and mechanical properties, it still lacks in antibacterial properties. Therefore, various surface modifications such as antibacterial coatings have been developed to enhance its properties. In this study, the surface of SS 316L was engineered with a thin multi-layer of tantalum oxide (TaO) and silver (Ag) with thickness of 4.7–6.4 μm. The thin film multilayered coatings were deposited using physical vapor deposition (PVD) magnetron sputtering. In this study, Ag/AgTa₂O₅ nanocomposite thin film is developed to avoid or limit bacterial adhesion on surgical tool surfaces. The as-deposited Ag/AgTa₂O₅ nanocomposite film were thermally treated to enhance the mechanical properties of the film. The thermal annealing of the as-sputtered thin film at 400 °C induced segregated Ag microstructure, increased the crystallinity and adhesion strength by about 152% (2916 ± 147 mN). The 400 °C annealed thin film exhibited hydrophobicity (102.5°) and thermal stability properties. The superior adhesion strength of the thermally treated film reduces and slows down delamination while in use at the rugged surgical environment.