Gold–silver core–shell nanoparticles stabilized with a common sweetener, aspartame (AuNP@Ag@Asm), combine the antimicrobial properties of silver with the photoinduced plasmon-mediated photothermal effects of gold. The particles were tested with several bacterial strains, while biocompatibility was verified with human dermal fibroblasts.

The passivity of titanium, binary Ti‐15Mo and ternary Ti‐15Mo‐5Al alloys in hydrochloric acid solutions was studied by potentiostatic, potentiodynamic, linear polarization and electrochemical impedance spectroscopy (EIS) techniques. The anodic passivity of binary Ti‐15Mo and ternary Ti‐15Mo‐5Al titanium alloys differs from that of the base metal in hydrochloric acid solutions. The corrosion potentials of both alloys are nobler than of the titanium because the beneficial effect of molybdenum. The critical passivation current density for binary Ti‐15Mo alloy is higher than of titanium; this fact can be explained by the instability of the constituent phases in hydrochloric acid solutions. Ternary Ti‐15Mo‐5Al alloy exhibits two critical passivation current densities (icr1 and icr2) with higher values than of the base metal and two critical passivation potentials (Ecr1 and Ecr2); at the first critical passivation potential (Ecr1) the porous titanium trioxide (Ti3O5) is formed and at the second critical passivation potential (Ecr2) this oxide is converted to a still higher valence oxide, the compact and protective titanium dioxide (TiO2). The dissolution current densities in the passive range of alloys are higher than of the base metal due the dissolution of the alloying elements in this potential range. The alloys are more resistant than titanium presenting lower corrosion rates. A three time constants equivalent circuit was fitted: one time constant is for the double layer capacity (Cdl) and for the passive film (Rp); another time constant is for the charge transfer reactions visualised by a constant phase element (CPE) and a resistance (R1); the third time constant is for diffusion processes through the passive film represented by a resistance (R2) and a Warburg element (W).

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The electrochemical impedance spectroscopy and the potentiostatic polarization techniques have been used to characterize the organic coatings electrodeposited on carbon steel. The coatings were formed during the cathodic and anodic electrodeposition of the modified epoxy resins on carbon steel samples previously polished and degreased (no primer was used). The experiments were conducted in stagnant, natural aerated 3% NaCl solution under ambient conditions. Analysis of the impedance spectra has established that an electrical equivalent circuit with two time constants fits to describe the electrodeposited epoxy coating/carbon steel system in the electrolyte solution. For the characterisation of the electrodeposited epoxy coatings the physical properties obtained from the principal elements of the equivalent electrical circuit and the electrochemical parameters obtained from the anodic polarization curves were used. It was established that these coatings present good performances characterized by low porosity, low water uptake and few conductive pathways and therefore a high efficiency. The coatings present a good adhesion to the carbon steels substrate; during the exposure period (60 days), no degradation or delamination process could be observed.

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The electrochemical impedance spectra, the anodic polarization curves and the time dependence of paint capacitance and paint resistance have been used in this paper to evaluate the protective properties of epoxy films on carbon steel substrate. The coatings were formed using four deposition techniques (brushing, immersion, cathodic and anodic electrodeposition) with the aim to determine the effect of deposition type on the anticorrosive performances of epoxy paint. Interpretation of Nyquist and Bode impedance spectra with the immitance analysis Equivcrt. programme has established an electrical equivalent circuit with two time constants fitted to describe the electrodeposited epoxy/carbon steel system in the 3 % sodium chloride solution and an electrical equivalent circuit with four time constants fitted in case of epoxy films applied by brush or immersion. The anodic polarisation measurements show nobler corrosion potentials and smaller dissolution current densities for the carbon steel in the presence of the electrodeposited films in comparison with epoxy coatings applied by brush or with the immersion technique. The values of the porosity, water uptake, and ionic transport through the film emphasize the higher performances of the electrodeposited films, characterized by uniformity, porosity absence, low water permeability and few conductive pathways.