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The corrosion behaviour of a commercial HR3C steel in a molten eutectic ternary Li2CO3-Na2CO3-K2CO3 mixture was studied by isothermal immersion tests at 700 °C and 800 °C for 2000 h. It was found that in both cases the corrosion products were arranged in a multilayer structure, with LiFeO2, LiCrO2, NiO and FeCr2O4 as the main compounds. Similar results to those obtained at 700 °C were reached in the tests performed at 800 °C but 1000 h earlier, which seems to indicate that the process was accelerated at higher temperature. Furthermore, regarding the superficial crystalline phase formed and according to the XRD and SEM examinations, it was found that on increasing the test temperature, a continuous transformation occurred from the rhombohedral to the cubic phase of the LiFeO2 oxide layer. This transformation took place at both temperatures when the tests proceed and it was also accelerated by increasing the temperature from 700 to 800 °C. Thus, the process seems to be slower at 700 °C, which complicates the use of HR3C at 800 °C in the molten eutectic ternary Li2CO3-Na2CO3-K2CO3 salt mixture. These results suggest that the use of protective coatings should be assessed and that this material should be tested at 700 °C under more aggressive conditions, such as flowing salt, in future studies.

This study assessed the behaviour of a constructive material in CSP plants, namelyferritic-martensitic steel, withmoltenNaNO3/KNO3(60/40 wt%), also known asSolar Salt. To this end, EIS is presented as a suitable technique to evaluate and monitor the resistance of this material to Solar Salt at 580 °C. Tests were performed up to 1000 h and results were also supported by gravimetric and microstructuralcharacterisationof the samples andchemical analysisof the salt. According to the EIS results, adiffusion-controlled reactionoccurred during contact, which indicates that the corrosion process follows aporous layermechanism. The results also indicated variations in corrosionlayer thicknessand instability of the salt during the whole test. The EIS results were also used for determining thecorrosion rate, this being estimated at ~300 µm year−1. Results obtained by EIS were in line with the behaviour of P91 steel as measured by gravimetric, morphological and chemical analysis. Thus, the results confirm the suitability of EIS for monitoring corrosion processes in real-time of constructive materials in CSP plants.

In this study, the corrosive behaviour of stainless alloy 321H when in contact with a Hitec-based quaternary salt mixture is assessed. Electrochemical impedance measurements were performed on the substrate-salt system, which was tested under static conditions at 500 °C for 1000 h. Results showed that corrosion in 321H is controlled by the ion transport through the oxide scale, and points to the presence of a protective layer mechanism. The fitting parameters showed that Rox diminishes sharply, from ∼84 Ω to 25 Ω, after the initial stages of the test. This indicates a reduction in the protective character of the oxide layer formed when the test runs. In addition, after 168 h of testing, Rt increased slightly, which indicates an increase in the number of species arisen from the substrate to the molten salt. In conclusion, the electrochemical results led to an estimated corrosion rate of 8.9 μm·year−1 for 321H steel. The results obtained by the corrosion monitoring system were in line with those obtained by Scanning Electron Microscopy and X-Ray diffraction. This study confirms the suitability of 321H stainless steel as a structural material for parabolic trough CSP technology and the enormous potential of the corrosion monitoring system for O&M processes. The next step is to scale up the proposed system for testing on a demonstration parabolic trough plant.

In the current work, 4 µm thick CrN/NbN coating utilising nanoscale multilayer structure with bi-layer thickness of ∆ = 2.9 nm has been used to protect 9 wt. % Cr steels such as P92 widely used in steam power plants. The uniquely layered coatings have a combination of nitrides of chromium and niobium which are not only resistant to aqueous corrosion and corrosion-erosion and have excellent tribological properties, but also have oxidation resistance in dry air up to a temperature of 850°C. The novel High Power Impulse Magnetron Sputtering (HIPIMS) deposition technology has been used to deposit CrN/NbN with enhanced adhesion (critical load of scratch adhesion LC2 = 80 N) and a very dense microstructure as demonstrated by Transmission Electron Microscopy (TEM) imaging. These superior coating properties are achieved due to the unique high metal ion content (up to 90%) in the HIPIMS plasma, which allows particle acceleration and trajectory control by external electrical and magnetic fields thus delivering highly energetic material flux on the condensing surface.\ud P92 bare and coated samples were oxidised at 650 °C in 100% steam atmosphere up to 2000 h, in order to simulate the future operation conditions of steam turbines employed in power plants. The oxidation kinetics was evaluated by mass gain measurements. Under these conditions CrN/NbN provided reliable protection of the P92 steel. The paper also discusses the effect of growth defects and high temperature crack formation analysed by Scanning Electron Microscopy and Focused Ion Beam-Scanning Electron Microscopy techniques (SEM and FIB-SEM, respectively) on the high temperature corrosion resistance in pure steam atmosphere thus revealing the coatings potential failure mechanisms.\ud Keywords : Thin films, Nitrides, Nano structures, Sputtering

A detailed analysis of the melting point and thermal degradation of a ternary mixture of carbonates to which various percentages of NaOH were added is presented. To this end, Differential Scanning Calorimetry (DSC) and Thermogravimetric Analysis (TGA) were carried out. Experimental results show that the melting point of the prepared salts can be down to below 450 °C with their decomposition temperatures around 900°C. The new kinds of mixed molten salts have a lower melting point and a slightly higher decomposition temperature, but the obtained improvements are not as large as expected. Therefore, it can be concluded that NaOH does not substantially improve the temperature operation range of the initial carbonate mixture.

El quiste óseo aneurismático es una patología infrecuente que asienta generalmente en las metáfisis de huesos largos y vértebras. La afectación del seno esfenoidal es excepcional. Su origen se encuentra aún por definir, pero podemos considerarlos como un fenómeno vascular secundario a una lesión del hueso subyacente. Puede asociarse a otras enfermedades, presentes de forma metacrónica o sincrónica en distintas localizaciones de un mismo sujeto, como la displasia fibrosa poliostótica o los tumores de células gigantes. En este artículo se expone el caso de un paciente que presenta un quiste óseo aneurismático en el seno esfenoidal y alteración de la visión.

Some drinks containing natural products with stimulant properties are highly consumed among young adults. The market for these drinks has increased in past years around the globe, and, although they might be harmless, overdoses or combination of these with other drinks could be harmful to the health of some consumers in certain circumstances. Samples were obtained at food shops and different popular brands were chosen. Cytotoxicity tests used were neutral red uptake, total protein content, and tetrazolium assay on Chinese hamster ovary cells. Results revealed that tested samples were not cytotoxic; however, studies have demonstrated the toxicity of high concentrations of some of these products. For this reason, the authors considered it to be of critical importance to carryout an in vitro toxicity screening of stimulant soft drinks that are highly consumed.