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Nickel-based coatings are well known for their good corrosion resistance performance. However, these materials suffer from inferior mechanical properties that limit their wider application. This work investigates the synthesis, and performs an exhaustive characterization, of Ni–P–B4C nanocomposite coatings developed through conventional electrodeposition using a modified Watts bath. The study examines the effect of an increase in the concentration of boron carbide nanoparticles (BCNPs) on the structural, morphological, topographical, mechanical and electrochemical properties of the nanocomposite coating. Vickers microhardness tester and nanoindentation technique were utilized to elucidate the role of BCNPs in modifying the mechanical response of nanocomposite coatings. Furthermore, corrosion resistance of the nanocomposite coatings was investigated through d.c potentiodynamic polarization and electrochemical impedance spectroscopy (EIS). Comparison of the properties of the developed coatings revealed the remarkable improvement in the properties of Ni–P–B4C nanocomposite coatings when compared to the bare mild steel substrate and the Ni–P coatings. The enhanced corrosion resistance and superior mechanical properties of Ni–P–B4C nanocomposite coatings make them attractive for many industries. Based upon the experimental findings, a possible mechanism for the synthesis and improved corrosion resistance of Ni–P–B4C nanocomposite coatings was also proposed.

Biodegradable scaffolds play a crucial role in biomedical restoration. These are three-dimensional (3D) structures that can provide support for the development of newly formed bone tissues. Among the studied metallic biodegradable scaffolds, those composed of iron (Fe) are notable for their high mechanical resistance. However, the slow degradation rate of Fe and the potential cytotoxicity of its degradation products pose challenges to effective osseointegration. Cerium oxide was incorporated into Fe scaffolds to overcome these two inherent limitations.

The increasing demand for energy storage devices requires sustainable practices for implementation, functionalization and recycling procedures that enable a circular economy with minimal wastes. Zinc and manganese are non-critical raw materials with an environmentally friendly character and proven merits in several energy storage solutions, amongst which supercapacitors, important electrochemical energy storage devices able to manage high-power, however lacking energy density. In this work, we demonstrate how these materials can be combined to improve the energy storage ability of manganese-based electrodes, through a simple, low-cost, and eco-friendly chemical precipitation method. The manipulation of manganese-based spinel was performed through the introduction of zinc, developing an enhanced electrochemical response in aqueous electrolyte media. A binary Mn3O4 + ZnMn2O4phase achieved a high specific capacitance of 238 F/g at 0.5 A/g in a 1 V potential window. This material displayed 80.5 % rate capability at 10 A/g, and excellent capacitance retention (97 %) after 5000 consecutive GCD cycles. Furthermore, the work evidences that the concentration of zinc in the ZnMn2O4structure can enlarge the active potential window up to 1.2 V, keeping high-rate reversibility. These electrodes reached a specific capacitance of 175 F/g at 0.5 A/g, 84 % rate capability at 10 A/g, and 78 % capacitance retention after 5000 consecutive GCD cycles. A comprehensive electrochemical study was performed to extract information on the energy storage mechanisms of the developed Manganese-based materials.

Scheme of the asymmetric supercapacitor cell and variation of the power density vs. the energy density for two aqueous electrolytes, 1 M Na2SO4and 1 M KOH.

•The degradation of bare and coated Mg-2Ca alloy was investigated in cell culture medium.•Decreased degradation of Mg-2Ca was attained with a PCL coating.•Embedded TiO2NPs in the PCL coating had further improved the corrosion resistance.•The PCL-TiO2coating delayed the corrosion and favored apatites precipitation when compared with PCL alone.

Free-standing graphene was synthesized using atmospheric pressure microwave plasma and used as electrode for supercapacitors. The graphene based electrodes demonstrated good supercapacitive and electronic properties and displayed a high rate retention of 78.5% and a low time constant of 0.2 s. It was further studied as conductive agent where the electrode produced after mixing it with activated carbon (AC) in 47.5:47.5 ratio demonstrated a specific capacitance of 208 F g−1at 2 A g-1, rate capability of 70.8% at 10 A g-1and a time constant of 4 s, significantly below the 25.1 s one obtained for electrodes made with commercial activated carbon and conductive agents. Electrodeposited FeCoS on stainless steel tested as positive electrode. The ratio of Fe to Co equal to 1:2 showed the best electrochemical performance with specific capacitance of 827.5 F g−1at 1 A g-1with a rate capability of 84.1% at 10 A g-1and long cycling stability of 90.4% up to 5000 cycles. An asymmetric cell made of AC:Graphene – 47.5:47.5||Fe:Co-1:2, displayed good capacitive response in a potential window of 1.2 V, in 1 M KOH, stored a maximum energy density of 67.8 W h kg-1at a power density of 1.6 kW kg−1and retained 45.2 Wh kg−1at a power density of 6.1 kW kg−1.

- Ferromagnetic stainless steels (SS) produced by powder metallurgy (PM) techniques have been investigated as potential candidates for dental prosthesis applications in replacement of magnetic attachments made of noble and expensive alloys. Two SS were investigated: SS 17-4 PH produced by powder injection (PIM) and SS PM2000 obtained by mechanical alloying. In vitro cytotoxicity analysis of the two SS showed no cytotoxic effects. The magnetic retention force of both tested SS was also evaluated and they were comparable to noble commercially available material that is in use at the moment. The corrosion resistance of both SS was evaluated by electrochemical techniques in sodium phosphate buffer solution (PBS) at 37°C. The AISI 316L SS was also tested under the same conditions for comparison reasons. SS samples tested showed passive behaviour in the electrolyte, but they also presented susceptibility to pitting. The best pitting resistance was associated to the PM2000 whereas the 17-4PH PIM showed the highest pitting susceptibility among the tested steels. The results pointed out that the PM2000 SS might be considered a potential candidate for substitution of high cost magnetic alloys used in dental prosthesis.

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•FeSxhaving different morphologies have been directly grown on stainless steel substrate by hydrothermal synthesis process.•Various synthesis periods have been explored to optimize the reaction conditions and corresponding reaction mechanism was proposed.•Specific capacitance of 730 mF cm−2at current density of 1 mA cm−2was achieved.•Interfacial redox kinetics responsible for charge storage is explored.•Asymmetric setup showed supercapacitive behaviour up to 1.8 V in aqueous electrolyte and delivered 236 mF cm−2at 0.5 mA cm−2.