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This paper presents corrosion resistance results of a 12Cr ferritic ODS steel (Fe-12Cr-2W-0.5Zr-0.3Y2O3) fabricated via a powder metallurgy route as a prospective applicant for fuel cladding materials. In a spent nuclear fuel reprocessing facility, nitric acid serves as the primary solvent in the PUREX method. Therefore, fundamental immersion and electrochemical tests were conducted in various nitric acid solutions to evaluate corrosion degradation behavior. Additionally, polarization tests were also performed in 0.61 M of sodium chloride solutions (seawater-like atmosphere) as a more general, all-purpose procedure that produces valid comparisons for most metal alloys. For comparison, martensitic X46Cr13 steel was also examined under the same conditions. In general, the corrosion resistance of the 12Cr ODS steel was better than its martensitic counterpart despite a lower nominal chromium content. Potentiodynamic polarization plots exhibited a lower corrosion current and higher breakdown potentials in chloride solution in the case of the ODS steel. It was found that the corrosion rate during immersion tests was exceptionally high in diluted (0.1–3 M) boiling nitric acid media, followed by its sharp decrease in more concentrated solutions (>4 M). The results of the polarization plots also exhibited a shift toward more noble corrosion potential as the concentrations increased from 1 M to 4 M of HNO3. The results on corrosion resistance were supported by LSCM and SEM observations of surface topology and corrosion products. [ABSTRACT FROM AUTHOR]

Magnesium (Mg) and its alloys offer promise for aerospace, railway, and 3D technology applications, yet their inherent limitations, including inadequate strength, pose challenges. Magnesium matrix composites, particularly with metallic reinforcements like titanium (Ti) and its alloys, present a viable solution. Therefore, this study investigates the impact of Ti6Al4V reinforcement on AZ31 magnesium alloy composites produced using pulse plasma sintering (PPS). Results show enhanced microhardness of the materials due to improved densification and microstructural refinement. However, Ti6Al4V addition decreased corrosion resistance, leading to strong microgalvanic corrosion and substrate dissolution. Understanding these effects is crucial for designing Mg-based materials for industries like petrochemicals, where degradation-resistant materials are vital for high-pressure environments. This research provides valuable insights into developing Mg-Ti6Al4V composites with tailored properties for diverse industrial applications, highlighting the importance of considering corrosion behavior in material design. Further investigation is warranted to establish predictive correlations between Ti6Al4V content and corrosion rate for optimizing composite performance. [ABSTRACT FROM AUTHOR]

The interest in the Spark Plasma Sintering (SPS) technique has continuously increased over the last few years. This article shows the possibility of the development of an SPS device used for material processing and synthesis in both scientific and industrial applications and aims to present manufacturing methods and the versatility of an SPS device, presenting examples of processing Arc-Melted- (half-Heusler, cobalt triantimonide) and Self-propagating High-temperature Synthesis (SHS)-synthesized semiconductor (bismuth telluride) materials. The SPS system functionality development is presented, the purpose of which was to broaden the knowledge of the nature of SPS processes. This approach enabled the precise design of material sintering processes and also contributed to increasing the repeatability and accuracy of sintering conditions. [ABSTRACT FROM AUTHOR]

Hemocompatibility is the most significant criterion for blood‐contacting materials in successful in vivo applications. Prior to the clinical tests, in vitro analyses must be performed on the biomaterial surfaces in accordance with the ISO 10993‐4 standards. Designing a bio‐functional material requires engineering the surface structure and chemistry, which significantly influence the blood cell activity according to earlier studies. In this study, we elucidate the role of surface terminations and polymorphs of SiC single crystals in the initial stage of the contact coagulation. We present a detailed analysis of phase, roughness, surface potential, wettability, consequently, reveal their effect on cytotoxicity and hemocompatibility by employing live/dead stainings, live cell imaging, ELISA and Micro BCA protein assay. Our results showed that the surface potential and the wettability strongly depend on the crystallographic polymorph as well as the surface termination. We show, for the first time, the key role of SiC surface termination on platelet activation. This dependency is in good agreement with the results of our in vitro analysis and points out the prominence of cellular anisotropy. We anticipate that our experimental findings bridge the surface properties to the cellular activities, and therefore, pave the way for tailoring advanced hemocompatible surfaces. [ABSTRACT FROM AUTHOR]

High temperature corrosion of thermoelectric materials is one of the most important issues linked with their application for power generation, especially in terrestrial conditions. The high chemical affinity of elements composing thermoelectric material to oxygen results in continuous degradation at high temperatures of most state-of-the-art materials. This issue is also well recognized in the case of antimonide skutterudites. The simplest way to protect against this process is the use of coatings. Complicated geometry of thermoelectric module favors coatings that can be deposited in a simple way on an assembled module. Such an opportunity, besides good thermal stability and appropriate thermal and electrical properties, is provided by amorphous silicon oxycarbide Si-O-C coatings. In this work, the results on Si-O-C coatings deposited on In0.4Co4Sb12 skutterudite are presented. The influence of heat treatment temperature and substrate roughness on the deposited layer is shown. Protective properties of the Si-O-C layer are presented by comparison of electrical conductivity and Seebeck coefficient of coated and uncoated samples, before and after isothermal oxidation in air at 430 °C for 24 h. In such conditions, the uncoated samples are distinctly oxidized (weight gain of 2.4%) with strongly affected electrical properties, while the coated samples show a slight weight gain of 0.1% and almost unchanged electrical properties. [ABSTRACT FROM AUTHOR]

Ferritic ODS steel elemental powder compositions with various Zr content (0.3–1.0 wt.%), ground in a Pulverisette 6 planetary ball mill, were extensively studied by X-ray diffraction line profile analysis, microscopic observations, microhardness testing and particle size measurements. A characteristic three-stage process of flattening the soft powders, formation of convoluted lamellae and, finally, formation of nanocrystalline grains was observed. In order to quantify the microstructural properties, expressed mainly in terms of crystallite size and dislocation density, a methodology for detailed and accurate microstructure analysis of nanosized and severely deformed materials was proposed by the Whole Powder Pattern Modelling (WPPM) approach. In the case of the proposed ODS alloy composition, the overlapping of Fe and Cr Bragg reflections makes the microstructure analysis certainly more complicated. The results showed that the microstructure of powders evolved towards the nanocrystalline state consisting of fine (diameter of ~15 nm) and narrowly dispersed domains, with extensive dislocation density exceeding 10 16 m−2. [ABSTRACT FROM AUTHOR]

Additive manufacturing (AM) has seen remarkable development in recent years due to relatively high efficiency of the process. Cold spraying (CS) is a particular method of AM, in which titanium and titanium alloy powders are used. CS is a very competitive technology enabling the deposition of coatings, repairing machine parts, and manufacturing new components. For specific applications, the surface of cold-sprayed materials may require further processing. This paper reports an attempt to employ laser surface treatment (LST) of cold-sprayed coatings on an aluminium alloy substrate. The influence of laser beam interaction time on the coatings' properties was analysed. The microstructure was investigated and observed employing scanning electron microscopy (SEM). To evaluate residual stress after CS and LST, the sin2ψ technique was used. Investigations were also performed on Vickers hardness, contact angle, and surface roughness. Significant changes in the surface morphology of the coatings and elevated residual stress levels dependent on the laser beam interaction time were observed. Increased Vickers hardness was recorded for titanium alloy Ti6Al4V. LST also led to increased surface hydrophilicity of the modified materials Ti and Ti6Al4V. [ABSTRACT FROM AUTHOR]

Doping is one of the possible ways to significantly increase the thermoelectric properties of many different materials. It has been confirmed that by introducing bismuth atoms into Mg sites in the Mg2Si compound, it is possible to increase career concentration and intensify the effect of phonon scattering, which results in remarkable enhancement in the figure of merit (ZT) value. Magnesium silicide has gained scientists’ attention due to its nontoxicity, low density, and inexpensiveness. This paper reports on our latest attempt to employ ultrafast self-propagating high-temperature synthesis (SHS) followed by the spark plasma sintering (SPS) as a synthesis process of doped Mg2Si. Materials with varied bismuth doping were fabricated and then thoroughly analyzed with the laser flash method (LFA), X-ray diffraction (XRD), scanning electron microscopy (SEM) with an integrated energy-dispersive spectrometer (EDS). For density measurement, the Archimedes method was used. The electrical conductivity was measured using a standard four-probe method. The See-beck coefficient was calculated from measured See-beck voltage in the sample subjected to a temperature gradient. The structural analyses showed the Mg2Si phase as dominant and Bi2Mg3 located at grain boundaries. Bismuth doping enhanced ZT for every dopant concentration. ZT = 0.44 and ZT=0.38 were obtained for 3wt% and 2wt% at 770 K, respectively [ABSTRACT FROM AUTHOR]

The aim of this study was to determine the effect of the support phase composition (Al2O3–TiO2) and the addition of gold on the catalytic properties in low-temperature CO oxidation. In this paper, the physicochemical properties and results of catalytic measurements performed for the obtained samples were investigated. The catalyst carriers were prepared using the sol-gel method with alkoxide Al(C3H7O)3 and Ti(C3H7O)4 employed to obtain the corresponding oxides, in the case of which the molar ratio (Al2O3:TiO2) was 0.75:0.25, 0.50:0.50 and 0.25:0.75, thus corresponding to the molar ratio of the Al:Ti elements, i.e. 1.5:0.25, 2:1 and 0.5:0.75 respectively. The gold catalysts were prepared through the deposition of gold by the deposition precipitation method using the theoretical loading of Au 2 wt.%. To examine the effect of the phase composition on the catalytic activity of the obtained samples, appropriate carriers were calcined at two different temperatures: 500°C and 1350°C. This made it possible to obtain the intended polymorphs of aluminum oxide and titanium dioxide (γ–Al2O3, α–Al2O3, anatase and rutile). For certain samples, calcined at a high temperature, the aluminum titanium oxide (Al2O5Ti) phase was also observed. The prepared samples were characterized by XRD, BET, SEM, and additionally both particle size distribution analysis and measurements of the catalytic activity were performed. The highest catalytic activity was shown by Au/75Al–25Ti_LT, where T90 was about 110°C.

The morphological characterization of a series of cobalt-cerium oxide composites prepared by the deposition of CeO2 onto Co3O4 powder with a molar ratio of cerium oxide to Co3O4 in the range of 0 to 1 was performed. The powders were also impregnated with a solution of K2CO3 to obtain the theoretical content of potassium atoms 2at·nm−2. To investigate the effect of adding specific amount of CeO2 on the catalytic activity, the X-ray diffraction, SEM-EDX, laser particle size distribution and BET surface area measurements were used. The catalysts were tested through the low-temperature decomposition of nitrous oxide in the temperature range of 50°C to 700°C. The addition of CeO2 and K always moved the temperature of a complete N2O conversion towards lower temperatures (480°C-540°C to 340°C-420°C). The best catalytic properties were shown by the samples in which the ratio of cerium oxide to cobalt oxide ranged from 0.4 to 0.7.

Cytocompatibility and hemocompatibility are essential features for tissue- and blood-contacting implants such as artificial heart valves, vascular grafts and stents. Platelet activation as the main trigger of thrombosis results in implant failures. The purpose of this study results from the demands on anti-coagulant and non-corrosive innovative biomaterials for cardiovascular implants. Therefore, hemocompatibility and cytocompatibility of various high-strength ceramics, such as alumina, zirconia, silicon nitride and silicon carbide, were examined to identify the most appropriate ceramic for cardiovascular implants. In addition to the material species, different crystallographic structures (single- and poly-crystalline) and surface terminations (Si and C faces) of silicon carbide were used in order to reveal the interactions between blood and material surface. Three cell types, i.e. human umbilical vein endothelial cells, mesenchymal stem cells and blood cells, were cultured on the substrates and their interactions with material surfaces were analyzed. Cytotoxicity of the materials was tested by live/dead staining. Hemocompatibility in terms of platelet and white blood cell activation was examined via scanning electron microscopy and indirect ELISA. To mimic physiological conditions in vitro, the hemocompatibility of the materials was additionally analyzed in a bioreactor under dynamic flow conditions in comparison to static incubation. All ceramics were found to be cytocompatible for mesenchymal stem cells, human umbilical vein endothelial cells and blood cells. The highest number of resting, non-activated platelets was observed on the monocrystalline silicon carbide demonstrating that this material triggers the platelet activation less compared to the other materials. It is found to be the most appropriate ceramic for blood-contacting implants in terms of cell adhesion, cell viability, and hemocompatibility. [ABSTRACT FROM AUTHOR]

The described method enables facile gram-scale preparation of CuFeS2 nanocrystals exhibiting interesting thermoelectric properties from simple and readily available precursors. Exchange of primary organic ligands for inorganic ones using either (NH4)2S or triethyloxonium tetrafuoroborate (Meerwein's salt) resulted in nanocrystals from which n-type bulk thermoelectric materials were obtained through sintering under pressure. The measured physical properties of the fabricated bulk thermoelectric materials depend on the type of inorganic ligands used for the exchange. In particular, materials that were surface-modified with Meerwein's salt have a higher Seebeck coefficient (|S| = 238 μV K-1) as compared to those modified with (NH4)2S, whereas the latter exhibit higher electrical conductivity (8500 S m-1) and lower thermal conductivity (0.5 W m-1 K-1), both of which are favorable for thermoelectric applications. [ABSTRACT FROM AUTHOR]

We report on the generation of 152-nJ Q-switched pulses in all-polarization-maintaining Er-doped fiber laser. The laser is passively modulated by the antimony telluride (Sb2Te3) layer sputtered on a surface of the side-polished fiber in order to exploit the evanescent field interaction in optically nonlinear material. The laser cavity is designed in an extremely simple way comprising, in addition to fibers, only one component and the saturable absorber, forming a robust, compact, and stable source of short pulses. The repetition rate might be tuned from 42 kHz up to 132 kHz. The shortest recorded pulse duration was the 857 ns. [ABSTRACT FROM AUTHOR]

Zirconia is commonly used for manufacturing of dental implants thanks to its excellent mechanical, biological and aesthetic properties. However, its bioinertness inhibits bonding with the surrounding hard tissue and other surface interactions. In our study, we present a method for multifunctionalization of zirconia surface to improve its osseointegration and to minimize the infection risks. For this reason, we introduced antibacterial and bioactive properties to zirconia surfaces by calcium phosphate biomimetic coating. The samples were incubated in vials in horizontal and vertical position in concentrated simulated body fluid (SBF) containing 0.1, 0.5, and 3 g/L of silver nanoparticles (Ag-NPs) and then were tested for their structure, surface properties, cytocompatibility and antibacterial properties. The results demonstrated that our method is suitable to introduce Ag-NPs at different concentrations into the calcium phosphate layer, i.e. from 0.05–26.6 atom% as shown by EDX. According to the results of CFU-assay these coatings exhibited antibacterial properties against S. aureus and E. coli in correlation with the concentration of Ag-NP. The potential cytotoxicity of the coated samples was determined by AlamarBlue® assay and live/dead staining of MG63 osteoblast-like cells in direct contact and by testing the extracts from the materials. Only samples containing 0.05 atom% Ag-NPs, i.e. incubated in vertical position at SBF with 0.01 g/L Ag-NPs, were found cytocompatible in direct contact with MG63 cells. On the contrary in the indirect tests, the extracts from all the materials were found cytocompatible. This method could allow developing the completely new material group, exhibiting not only one but several biological properties, which can improve osseointegration and minimize infection risks. [ABSTRACT FROM AUTHOR]

We report a study on a hybrid mode-locked fiber laser with two saturable absorbers: slow and fast, integrated in a single device. Amorphous antimony telluride (Sb(2)Te(3)) layer was deposited on side-polished fiber to form the slow saturable absorber due to the third order nonlinear susceptibility of Sb(2)Te(3). Additionally, an unsymmetrical design of the device causes polarization-dependent losses and together with polarization controller allows to use a nonlinear polarization evolution to form the artificial fast saturable absorber. Sub-200 fs soliton pulses with 0.27 nJ of pulse energy were generated in the hybrid mode-locked Er-doped fiber laser. Differences in the dynamics of mode-locked laser are further investigated with the use of slow and fast saturable absorbers solely, and compared with the hybrid device. Joint operation of two saturable absorbers enhances the laser performance and stability. The conducted experiments allowed to define roles of each mechanism on the pulse shaping in the laser cavity.