The Boston keratoprosthesis (BKPro) is a critical device for vision restoration in complex cases of corneal blindness, although its long-term retention is challenged by infection risks. This study aims to enhance the antimicrobial properties of the titanium (Ti) backplate of the BKPro by ion implanting silver and copper ions to achieve effective infection control while maintaining cytocompatibility. Research on antimicrobial modifications for BKPro is limited, and while metallic ions like Ag and Cu show promise for biomaterial improvement, their effects on human corneal keratocytes (HCKs) require further study. Ag and Cu were implanted onto rough Ti surfaces, as mono- and coimplantations. Cytotoxicity was assessed in HCKs, and antimicrobial efficacy was tested against Pseudomonas aeruginosa and Candida albicans . After 21 d, monoimplanted Ag samples released 300.4 ppb of Ag ⁺ , coimplanted samples released 427.5 ppb of Ag ⁺ and 272.3 ppb of Cu ions, and monoimplanted Cu samples released 567.0 ppb of Cu ions. All ion-implanted surfaces supported HCK proliferation, exhibited no cytotoxicity, and showed strong antimicrobial activity. Ag-implanted surfaces provided antibacterial effects through membrane disruption and reactive oxygen species generation, while Cu-implanted surfaces exhibited antifungal effects via impaired enzymatic functions and reactive oxygen species. Coimplanted AgCu surfaces demonstrated synergistic antimicrobial effects, resulting from the synergy between the bactericidal actions of Ag and the oxidative stress contributions of Cu. Additionally, ion-implanted surfaces enhanced HCK adhesion under co-culture conditions. In conclusion, ion implantation effectively imparts antimicrobial properties to the Ti backplate of BKPro, reducing infection risks while preserving compatibility with corneal cells.

The use of lightweight materials, such as ultra-high-strength aluminium alloys, is in high demand in the automotive and aerospace industries where weight savings are critical. The tool materials used for high-speed cutting of these aluminium alloys are subjected to severe conditions that promote premature failure of cutting tools. The application of polycrystalline diamond (PCD) coatings provides cutting tools with increased mechanical and thermal fatigue resistance and improved tribological performance. Despite these good properties, their high cost remains a major limitation in this sector. Super-hard Diamond-Like Carbon (DLC) coatings offer a technologically and economically feasible alternative to PCD-coated tools for cutting and machining non-ferrous materials. In this paper, the machining performance of coated and un-coated hard metal inserts in the turning of 7075 aluminium alloy has been explored. The surface quality of machined parts, the cutting tool wear resistance and the vibrations generated during turning of un-coated, PCD and super-hard thin DLC coatings on tungsten carbide inserts were compared. The results obtained demonstrate that DLC coatings are a potentially interesting alternative to PCD coatings for machining ultra-high-strength aluminium alloys, where surface component finish is a key factor.

This study explores the impact of Zr and Ta ion implantation on the mechanical performance of an AlCrSiN quaternary coating deposited on a WC-Co cermet substrate. Nanoindentation tests revealed a decrease in hardness and elastic modulus after ion implantation, compared to unimplanted coatings. Moreover, microscratch and contact damage tests demonstrated improved adhesion and reduced surface damage for ion-implanted samples, with Ta implantation exhibiting the best performance. Scanning Electron Microscopy (SEM) and focused ion beam (FIB) cross-sectional analysis confirmed less severe damage in ion-implanted samples compared to unimplanted ones. These findings suggest that Zr/Ta ion implantation enhances the structural integrity and adhesion of AlCrSiN coatings under loading conditions commonly encountered in practical applications, despite a moderate reduction in intrinsic hardness and elastic modulus.

Ion implantation has been shown to improve adhesion strength of AlCrSiN coatings due to a synergic enhancement on fracture toughness and load bearing capability of the substrate that can potentially increase the in-service efficiency of coated cutting tools. In this work, AlCrSiN coatings deposited by PVD on WC-Co substrates implanted with Ti, Cr and N ion species have been processed. The mechanical properties and adhesion have been characterized by contact techniques and the residual stress of the coatings and substrates have been evaluated using FIB-DIC technique and Vickers indentation tests, respectively. An improvement of adhesion strength is obtained for treated substrates, especially for those implanted with titanium and chromium ions. This improvement is attributed to the introduction of residual stresses in the substrate, which increases its fracture toughness and enhances its load bearing capability.