In aircraft and storage fuel tanks, many environmental corrosion factors can be present, which can cause breakdown to the passive film of aluminum causing severe localized corrosion. Aiming to a solution to this problem, diamond-like carbon (DLC) films were deposited on substrates Al 2024-T3, Al 5052-H32, and Al 6061-T6. The substrates with and without DLC films were submitted to a corrosive immersion test with aviation fuel Jet-A1 and AVGAS 100LL. The surface morphology from aluminum substrates with and without DLC films was analyzed before and after 7 and 30 days of corrosive immersion tests by SEM. The adhesion of the DLC films was evaluated according to the ASTM-C1624 scratching test standard, and the optical profilometry was used to measure the thickness and roughness. Silver nanoparticles were also added in DLC films samples due to its antibacterial properties to check the stability and resistance against corrosive fuel medium. The results indicated an improvement of corrosion resistance just with DLC films. The silver nanoparticles did not present any advantages in this corrosion protection, and the aluminum alloys suffered more corrosion than when protected by DLC films. K E Y W O R D SAl 2024-T3, Al 5052-H32, Al 6061-T6.

Stainless steel 316L (SS316L) and titanium-alloy Ti6AL4V exhibit properties for bio-medical applications; however their tribocorrosion associated with metallosis is still a major concern. Therefore smoothing DLC coatings aiming for the improvement of tri-bocorrosion and cell viability of stainless steel 316L (SS316L) and titanium-alloy Ti6AL4V with and without DLC coatings were compared. The motivation was due to many papers detailing metallosis caused by metal debris in the body's soft tissues. Nowadays, metallosis is responsible for almost of prosthesis replacement surgeries. DLC coatings were produced using the Plasma Enhanced Chemical Vapor Deposition (PECVD) technique; acetylene gas was used as a carbon precursor, and silane gas produced an amorphous silicon interface between the DLC coating and metal substrate. A combined setup of techniques thoroughly evaluated the coatings considering chemical composition, coatings adhesion at a metallic substrate, scratch resistance, and tribocorrosion susceptibility. The cytotoxicity and genotoxicity of metallic samples with and without DLC coatings were analyzed, considering cell viability and its correlation with coatings’ chemical composition

Polyurethane (PU) substrates are biocompatible materials widely used to manufacture endotracheal tubes. However, in common with other biomedical materials, they are liable to the formation of microbial films. The occurrence of pneumonia in intubated patients treated at intensive care units (ICUs) often takes the form of ventilator-associated pneumonia (VAP). The issue relates to the translocation of pathogenic microorganisms that colonize the oropharyngeal mucosa, dental plaque, stomach, and sinuses. New protective materials can provide a more effective therapeutic approach to mitigating bacterial films. This work concerns microcrystalline carbon film containing dispersed silver nanoparticles (μC-Ag) deposited on PU substrates using a physical vapor deposition (PVD) sputtering process. For the first time, carbon paper was used to produce a carbon target with holes exposing a silver disk positioned under the carbon paper, forming a single target for use in the sputtering system. The silver nanoparticles were well distributed in the carbon film. The adherence characteristics of the μC-Ag film were evaluated using a tape test technique, and EDX mapping was performed to analyze the residual particles after the tape test. The microbicidal effect of the thin film was also investigated using species S. aureus, a pathogenic microorganism responsible for most infections of the lower respiratory tract involving ventilator-associated pneumonia (VAP) and ventilator-associated tracheobronchitis (VAT). The results demonstrated that μC-Ag films on PU substrates are promising materials for mitigating pathogenic microorganisms on endotracheal tubes.

Bacterial contamination in hospital environments is a significant concern for patient admissions. Aiming to reduce contamination, titanium dioxide film (TiO2) in the anatase phase has been prepared on the surface of polyvinyl chloride (PVC) tubes. The PVC tube material was used to study the film’s effectiveness in inhibiting bacterial growth and cell viability. The morphology and composition of deposited films were investigated using a Scanning Electron Microscope (SEM) and Energy Dispersive Spectroscopy (EDS) map. In addition, Fourier-Transform Infrared Spectroscopy (FTIR) and XRD diffractogram were used to analyze film composition and phase, respectively. The adhesion of TiO2 film on PVC substrate was determined using Scotch™ tape-test according to ASTM: D3359-09, 2010, and the film surface morphology was analyzed by the MEV-FEG technique and EDS map. The bacterial viability was performed with Staphylococcus aureus, and cell viability was performed using L929 strain mouse fibroblasts. The results of TiO2 in the anatase phase deposited by ALD on the PVC surface demonstrate good adherence and the film’s effectiveness in inhibiting bacterial growth and cell viability.