Recently, the new updates in legislation about drinking water control and human health have increased the demand for novel electrochemical low-cost sensors, such as potentiometric ones. Nowadays, the determination of chloride ion in aqueous solutions has attracted great attention in several fields, from industrial processes to drinking water control. Indeed, chloride plays a crucial role in corrosion, also influencing the final taste of beverages, especially coffee. The main goal is to obtain devices suitable for continuous and real-time analysis. For these reasons, we investigated the possibility to develop an easy, low-cost potentiometric chloride sensor, able to perform analysis in aqueous mediums for long immersion time and reducing the need of periodic calibration. We realized a chloride ion selective electrode made of Ag/AgCl sintered pellet and we tested its response in model solutions compatible with drinking water. The sensor was able to produce a stable, reproducible, and accurate quantification of chloride in 900 s, without the need for a preliminary calibration test. This opens the route to potential applications of this sensor in continuous, in situ, and real time measurement of chloride ions in industrial processes, with a reduced need for periodic maintenance.

Modification of surface properties with the purpose of improving resistance, hardness, and endurance is a common practice in most industrial applications. However, the fashion industry has a more complex goal of meeting customers' aesthetic tastes while maintaining quality and mechanical properties with safety characteristics. The use of galvanic coatings on metal substrates allows for a good compromise among all these requirements, but toxic solvents combined with nickel and chromium(VI) baths heavily impact the environment and human health. For this reason, alternative approaches have been studied, and we propose Physical Vapor Deposition (PVD) coatings as a good alternative. The objective of this study is to develop protective coatings in Cr/CrN for brass substrates using the PVD technique. PVD is an mature and very stable technique, the use of which was limited until now by the high costs of the vacuum system and targets. The environmental impact of PVD is very low, and a wide range of coatings with elevated purity can be prepared, such as metallic, ceramic, nitrides, and oxides. Brass substrate is commonly used in the manufacturing industry because of some interesting properties, such as ductility, resistance, and a low melting point, which allows for low-temperature processing and low costs. However, brass is known to have inadequate corrosion resistance, which negatively impacts the quality of the final products. For this reason, there is a need to look for coatings that improve the corrosion resistance of brass, keeping a shiny and smooth aspect with desirable colors. Chromium Nitride is an extremely hard, inert, thin film that is applied primarily to precision metal parts. CrNx also performs well in corrosive environments and in sliding wear applications. Precisely, CrNx is an interstitial compound with nitrogen atoms occupying the octahedral holes in the chromium lattice. This characteristic opens the door to interesting investigations: by modifying the chamber pressure and N₂/Ar flow, one can obtain films with different stoichiometry. In this study, five thin films of 350 nm of Cr/CrN were prepared by changing the ratio of N₂/Ar in the chamber from 0.2 to 0.6. Using Scanning Electron Microscopy (SEM), we investigated the homogeneity of the coatings and estimated the percentage of defects formation. The chemical composition was analyzed with Energy Dispersive X-ray Spectroscopy (EDS-SEM), while the color coordinates were estimated with a Spectrophotometer. In parallel, we investigated the thickness and structure combining SEM with XRF technique [1]. As a result of this study, we selected the 0.4 ratio N₂/Ar for CrNx layers, which agreed with literature [2], and created a multilayer film of Cr/CrN. Finally, we tested different combinations of engineered multilayer films with electrochemical tests such as free corrosion test OCP, Electrochemical Impedance Spectroscopy (EIS), and neutral salt spray (NSS) test (ISO 9227:2017). Then, we compared the results to understand and optimize which condition combinations are more suitable for protective applications. In conclusion, by deepening the knowledge on this topic, it might be possible to play with the pressure conditions in the chamber to open new design possibilities. References: [1] Giurlani et al. Coatings 2018, 8, 84. [2] Grzegorz Greczynski et al. IEEE Transactions on plasma science, vol. 38, no. 11, November 2010

Microplastics (MPs) have been attracting considerable interest in recent years due to their ubiquitous existence and accumulation within different systems and ecosystems. Moreover, their presence in electroplating baths involves a more serious challenge considering that the electroplating industry is progressing towards the electroplating of plastic materials. Contaminated baths can lead to surface defects, poor adhesion, corrosion, and inconsistent deposit thicknesses. Despite these issues, the interactions between pollutant MPs and heavy metal ions in electroplating environments are still underexplored. The present study aims to investigate the behavior of self-produced “Nylon PA” MPs dispersed in acid copper electroplating baths and their interactions with copper ions in solution. Scanning electron microscopy (SEM) reveals several surface defects in copper deposits caused by MPs in the bath. Additionally, cyclic voltammetry and chronoamperometry indicate significant changes in nucleation and growth mechanisms, with MPs showing suppressant-like effects on copper deposition. These results shed light on the impact of MPs on copper electrodeposition, emphasizing the urgent need for further research and mitigation strategies to address this emerging issue in the electroplating industry.