Recently, the use of graphene as a conductive nanofiller in the preparation of inorganic/polymer nanocomposites has attracted increasing interest in the aerospace field. The reason for this is the possibility of overcoming problems strictly connected to the aircraft structures, such as electrical conductivity and thus lightning strike protection. In addition, graphene is an ideal candidate to enhance the anti-corrosion properties of the resin, since it absorbs most of the light and provides hydrophobicity for repelling water. An important aspect of these multifunctional materials is that all these improvements can be realized even at very low filler loadings in the polymer matrix. In this work, graphene nanoflakes were incorporated into a water-based epoxy resin, and then the hybrid coating was applied to Al 2024-T3 samples. The addition of graphene considerably improved some physical properties of the hybrid coating as demonstrated by Electrochemical Impedance Spectroscopy (EIS) analysis, ameliorating anti-corrosion performances of raw material. DSC measurements and Cross-cut Test showed that graphene did not affect the curing process or the adhesion properties. Moreover, an increment of water contact angle was displayed.

Mg and Mg alloys have been studied for almost two centuries; nevertheless, commercial biomedical devices are still not available. The main issue that limits their use in the biomedical field is the rapid degradation rate combined with suitable surface properties. Novel approaches need to be designed for the development of biodegradable Mg-based devices, which could include the use of multifunctional coatings and/or new alloys designed “ad hoc”. The present article reviews on various properties, parameters and improvement methods concerning plasma electrolytic oxidation (PEO) coatings on Mg alloys substrates for biomedical applications. In this regard, (i) optimizing the PEO parameters, (ii) using additives and nanoparticles, (iii) creating combined layers of hard and/or soft particles, (iv) coating the PEO layer with a biodegradable polymer, could be the way to control their degradation rate. The review of recent scientific articles highlights that none of the techniques proposed may be preferred over the others and the need to deepen the studies for allowing the use of Mg-based devices in the biomedical field.

Recently, additive manufacturing technologies have begun to play a significant role in the industrial field due to the possibility to build complex, near‐net‐shape, and porous parts, optimizing costs, and time processing. Simultaneously, the high roughness of additively manufactured parts remains a critical drawback, limiting their use like an as‐built component. Therefore, postprocessing treatments are needed. The electropolishing (EP) treatment could be ideal for simple, complex, or porous parts characterized by low surface quality. Herein, it is aimed to provide the state of the EP treatment's art carried out, to date, on additively manufactured parts made of titanium and Ti6Al4V alloy. A scientific literature research on EP of additively manufactured titanium and Ti6Al4V alloy is conducted using the Scopus database. The evaluation of recent research, still very few to date, reveals that a significant reduction of the roughness can also be achieved in complex shape additively manufactured parts. Although the EP is a versatile technique to reduce the roughness of additively manufactured parts, further studies are needed to improve its effectiveness, especially for complex and porous structures, to reduce the environmental impact of the materials used.

Machined devices made of titanium or titanium alloys are widely used in biomedical applications. Recently, additive manufacturing technologies (AM) were proposed to reduce the cost of parts and customise their shape. While several researchers have studied the characterisation of the machined surfaces of AM products, less attention has been focused on the study of the surfaces of as-produced parts. The aim of this study was to compare the surface and bulk properties of Ti-6Al-4V alloy products obtained using two types of AM—i.e., electron beam melting and direct metal laser sintering—in comparison to the wrought material and analyse their metallographic, crystallographic, topographic, and electrochemical properties. The metallographic and crystallographic, as well as topographic, analysis showed different microstructures and surface area extensions between the tested specimens. Potentiodynamic polarisation tests highlighted the complex electrochemical behaviour of additively manufactured parts if compared to that of the traditionally fabricated ones. The tests performed on mechanically polished parts underlined similar electrochemical performance between them, even if the additive manufactured ones exhibited a certain instability. Although the as-produced additive manufactured parts present exciting surface shapes, useful in the biomedical field, significant drawbacks remain. A more in-depth study of the device surface modifications, to improve their electrochemical behaviour, is needed.

Additive manufacturing technologies have several well-known advantages; however, the surface quality of the printed parts is poor, compromising the corrosion and mechanical properties. Thus, surface finishing treatments are necessary. The most post-processing treatments proposed in the literature are mechanical or chemical. The formers are contact techniques and cannot be suitable for complex geometry, while the latter use strong and dangerous reagents. This paper is aimed to investigate the effect of the electropolishing treatment, a contactless technique, using an eco-friendly electrolytic solution in reducing the roughness and improving the fatigue properties of Ti6Al4V specimens produced by electron beam melting technology. Several parameters affecting the effectiveness of the electropolishing treatment have been investigated, as interelectrode distance, stirring rate and duration time. An optimal combination of them allowed a uniform surface treatment and a significant roughness reduction (64% of Sa reduction for cylindrical specimens). Under sinusoidal loading conditions with a maximum stress of 378 MPa and a stress ratio equal to R = 0.1, the mean fatigue life of electropolished dog-bone specimens was 250% longer than that of as-built specimens.

Titania nanotubes are widely studied for their potential applications in several fields. In this paper, the electrochemical characterization of a dental implant, made of commercially pure titanium grade 2, covered by titania nanotubes, when immersed in Hank’s solution, is proposed. Few papers were found in the scientific literature regarding this topic, so a brief review is reported, concerning the use of some equivalent circuits to model experimental data. The analysis of results, obtained by using Electrochemical Impedance Spectroscopy, showed that: (i) a good correlation exists between the variation of E_corr and the estimated values of the charge transfer resistance for both the bare- and the nanotube-covered samples, (ii) the nanostructured surface seems to possess a more active behaviour, while the effect could be over-estimated due to the real extent of the surface covered by nanotubes, (iii) the analysis of the “n” parameter, used to fit the experimental data, confirms the complex nature of nanostructured layer as well as that the nanotubes are partially filled by compounds containing Ca, P and Mg, when immersed in Hank’s solution. The results obtained in this work give a better understanding of the electrochemical behaviour of the nanotubes layer when immersed in Hank’s solution and could help to design a surface able to improve the implant osseointegration.