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•Bottom electrode has a strong influence on the growth of the active layer.•LaNiO3 electrode strongly stabilizes the perovskite phase.•Stabilization is mainly related to increased ...interface roughness.•Increased interface roughness does not have adverse effects on the film properties.
Pulsed-laser deposition was used to prepare Pb(Mg1/3Nb2/3)O3-PbTiO3 (PMN-PT) thin films on (LaNiO3)/SrTiO3 substrates. We found that the bottom electrode has an immense influence on the properties of the overgrown active layer. Specifically, we found that the use of LaNiO3 (LNO) as the electrode material strongly stabilizes the perovskite phase and significantly expands the process window for the preparation of phase-pure PMN-PT as compared to a direct deposition on SrTiO3 (STO) substrates. Based on our experiments, the stabilization is achieved primarily due to the increased interface roughness, which enhances the sticking of Pb-based species, thereby suppressing the formation of undesired Pb-deficient pyrochlore inclusions. The roughness of the interface does not have adverse effects on the quality of the films. In fact, the film prepared on the LNO/STO template from the Pb-rich target exhibited superior electrical properties as compared to the film prepared directly on STO. By understanding the mechanism, we were able to exploit it and prepare an STO/Nb:STO template with a rough surface, which strongly enhanced the stability of the perovskite phase. This approach can be used to design templates for different device configurations.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
The green transition initiative has exposed the importance of effective recycling of Nd-Fe-B magnets for achieving sustainability and foreign independence. In this study, we considered strip-cast, ...hydrogenated, jet-milled Nd-Fe-B powder as a case study to explore the potential for selective chemical leaching of the Nd-rich phase, aiming to extract the Nd2Fe14B matrix phase. Diluted citric and nitric acids at concentrations of 0.01, 0.1, and 1 M were considered potential leaching mediums, and the leaching time was 15 min. Microstructural investigation, magnetic characterization, and elemental compositional analysis were performed to investigate leaching efficiency and selectivity. Based on SEM analysis, Nd/Fe ratio monitoring via ICP-MS, and the high moment/mass value at 160 emu/g for the sample leached with 1 M citric acid, 1 M citric acid proved highly selective toward the Nd-rich phase. Exposure to nitric acid resulted in a structurally damaged Nd2Fe14B matrix phase and severely diminished moment/mass value at 96.2 emu/g, thus making the nitric acid unsuitable for selective leaching. The presence of hydrogen introduced into the material via the hydrogen decrepitation process did not notably influence the leaching dynamics. The proposed leaching process based on mild organic acids is environmentally friendly and can be scaled up and adopted for reprocessing industrial scrap or end-of-life Nd-Fe-B magnets to obtain single-phase Nd-Fe-B powders that can be used for novel magnet-making.
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IZUM, KILJ, NUK, PILJ, PNG, SAZU, UL, UM, UPUK
An antimicrobial finishing for cotton fabric was prepared from commercial (iSys AG, Germany) silver chloride (Ag) dispersed at different concentrations in a reactive organic–inorganic binder (RB) ...(iSys MTX (CHT, Germany). Pad-dry-cure and exhaustion methods were used for the sols application, giving Ag-RB coating with Ag concentration from ca. 48 to ca. 290
ppm on the cotton fabric. The presence of silver on the cotton finishes was confirmed by measuring its concentration in the fabrics with the help of inductively coupled plasma mass spectroscopy (ICP-MS). The morphology of the finished fabrics was investigated by SEM, while their composition was established from EDXS measurements combined with the results of FT-IR spectral analysis. The antimicrobial activity of variously treated cotton fabrics was assessed before and after repetitive (up to 10×) washing by the application of standard tests: for the fungi
Aspergillus niger (ATCC 6275) and
Chaetomium globosum (ATCC 6205) by the modified DIN 53931 standard method, while the presence of Gram-negative bacterium
Escherichia coli (ATCC 25922) was followed by using ISO 20645:2004 (E) and AATCC 100-1999 standard methods. Results revealed that the antimicrobial activity of the coatings strongly depended on the concentration of Ag in the corresponding Ag-RB dispersions, indirectly depending on the preparation method (pad-dry-cure vs. exhaustion) and that the Ag-RB coatings were more effective for bacteria than for fungi. The Ag concentrations on the cotton fabrics achieved by the pad-dry-cure method (48 and 52
ppm) were not sufficient to impart satisfactory antifungal activity to the cotton fabrics, though they assured excellent reduction of the bacterium
E. coli (98–100%). A minimal inhibitory concentration of Ag in the coating providing a sufficient bacterial reduction of 60% was ca. 24
ppm. Effective antifungal activity was achieved only by applying the exhaustion method, enabling high initial Ag concentration in the Ag-RB coating (>100
ppm). The antibacterial activity depended on the washing treatment. No antifungal activity was noted for washed cotton fabric, even those with highly concentrated Ag (290
ppm) in the Ag-RB coating, but a 94% bacterial reduction was obtained for the corresponding cotton fabric, after 10 repetitive washings, corroborated by the Ag concentration on washed fabric of about 65
ppm.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK
Flat panel display technology seems to be an ever‐expanding field developing into a multibillion dollar market. A set of technical solutions involve a transparent conducting film (TCF) that is today ...still dominated by indium‐tin‐oxide (ITO). In a race to find alternatives that would avoid the indium pitfalls, mainly due to its increasing price and limited natural availablity, replacement materials have been extensively investigated. This work demonstrates that by exploiting basic principles of crystal growth in geometrically constrained conditions, zinc oxide (ZnO) could easily be utilized for this purpose. ZnO layers were grown on inexpensive glass substrates via low‐temperature citrate‐assisted hydrothermal (HT) method. It was shown that in the nucleation stage the crystal growth can be efficiently controlled by spatially confined oriented growth (SCOG) mechanism to produce smooth and dense (0001) oriented polycrystalline ZnO films with superb optical properties. Our products show optical transparency of 82% and surprisingly low sheet resistance for undoped ZnO, only in the order of few 100 Ω sq−1. We believe that a very high degree of self‐organization between the ZnO crystals in our polycrystalline films grown under controlled SCOG conditions is main reason for the highest so far reported transparency to conductivity ratio for undoped ZnO thin film ceramics.
In a race to find alternatives to indium‐tin‐oxide (ITO) in flat panel display technology, replacement materials are extensively investigated. The basic principles of crystal growth under geometrically constrained conditions are exploited to manufacture highly transparent (82%) and conductive (100 Ω sq−1) ZnO films on inexpensive glass substrates.
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BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SBCE, SBMB, UL, UM, UPUK
We examined the effect of Al59Cu25Fe13B3 (at.%) quasicrystalline (QC) reinforcement particles on the mechanical and surface properties of a polymer-matrix composite by applying a technical polymer ...polyphthalamide (PPA). The observed increase in the tensile Young’s modulus ranged from 1810 MPa for the pure polymer to 4114 MPa for the composite with a QC filling of 35 vol.%. The elongation at fracture decreased with the filling fraction, being equal to 16.9% for a pure polymer and dropping to 4.8% for the composite with a QC filling of 35 vol.%. The same trend was noticeable with flexural Young’s modulus, which ranged from 100 MPa for a pure polymer to 125.5 MPa for the composite with 35 vol.% of QC. It was found that the increase in the mechanical strength led to a simultaneous increase of brittleness, which was reflected in a decrease of the impact strength for a pure polymer from 98.5 kJ/m2 to 42.4 kJ/m2 for composites with a QC filling of 35 vol.%. In contrast, when filled with 5 vol.% of QC, the impact strength increased by 8%. The friction coefficient against 100C6 steel dropped from 0.15 for pure PPA down to 0.10 for 5 vol.% of the QC filling, followed by an increase to 0.26 for further QC fillings up to 35 vol.%. Interestingly, a local minimum of friction was achieved at filling factors between 5 to 20 vol.% of QC. Independently, a clear surfenergy minimum was also found for the composite material with 20 vol.% of QC filling associated with a net drop in the polar component of the surfenergy. Surfenergy refers to the surface energy related to the top of the oxide layer under ambient conditions. We hypothesise that this is related to the percolation threshold at about 13 vol.% QC, reflected in the observed behaviour of both the friction coefficient and surfenergy. For the pure QC annealed in air for 1 h at 500 °C significant wear tracks were observed accompanied by a wear debris formation. On the other hand, a pure polymer exhibited slightly visible wear tracks with no apparent debris formation, and for the composites with different QC filling factors, the wear traces were barely visible with negligible debris formation.
Bisphenol S (BPS) is a common, persistent, and mobile chemical found in everyday products such as thermal paper. BPS can easily enter the body by migrating from the paper to the fingers, disrupting ...the endocrine system by mimicking the oestrogen hormone, thus negatively influencing human health. Assessing BPS levels in daily life is of great importance. This study introduces a rapid and reliable approach for detecting BPS in thermal paper and tap water by developing an electrochemical analytical method. This method allows for in-situ, real-time measurements. We present a simple, low-cost electrochemical sensor for detecting BPS using screen-printed electrodes based on carbon (SPEC) and single-wall carbon-nanotube (SPE-SWCNT) working electrodes. BPS was detected over a wide linear range from 1 to 400 μM. The detection limits were 0.73 μM and 0.87 μM for the SPE-C and SPE-SWCNT electrodes, respectively. Good repeatability was observed for both sensors when using one electrode 16 times, which demonstrates its potential for real-time environmental monitoring. Additionally, traditional chromatographic methods, high-performance liquid chromatography with a diode-array detector (HPLC-DAD), and liquid chromatography-mass spectrometry triple quadrupole (LCMS), were incorporated to enhance analytical capabilities. HPLC-DAD achieved a detection limit of 3 nM after solid-phase extraction preconcentration, while LCMS triple quadrupole demonstrated a detection limit of 10 pM without preconcentration. Electrochemical screen-printed electrodes can be employed for on-site analysis and health-risk assessments in everyday settings, such as shops. However, for detecting very low concentrations where time is not a constraint, LCMS quadrupole remains the preferred technique.
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•BPS is potential endocrine-disrupting chemical that can be found in thermal paper.•Fast detection and monitoring of BPS by portable electrochemical sensors.•Detection of BPS in pM concentration by LCMS-triple quadrupole.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
Super-hydrophobic surfaces and coatings have stimulated a great deal of research, with the aim being to achieve better wetting properties. Factors such as surface chemistry and roughness play an ...important role in changing the surface energy, which in turn leads to changes in the wettability. Here, we have analysed the time dependence of the oxide layer and possible surface adsorbates on the surface topography of an Al59Cu25Fe13B3 quasicrystalline material in relation to changes in the wettability. The quasicrystalline matrix phase was 94% of the sample volume, and it was covered by a very smooth, amorphous oxide layer. The AlB12 and AlFe2B2 boron-rich phases were embedded in the quasicrystalline material as a result of the 3 at.% boron addition, which made atomisation of the material a simpler process. Under ambient conditions, the sample was naturally covered by an oxide layer; therefore, it is referred to as “surfenergy” to distinguish it from the conventional surface energy of a bare quasicrystal surface. The growth of the oxide layer with atmospheric ageing and annealing at 500 °C in air for various times was investigated for both cases. The phase most prone to oxidation was the boron-rich AlFe2B2, which influenced the topography of the surface and accordingly the wetting behaviour of the specimen. We demonstrated that the surfenergy depends on the polar component, which is the most sensitive to the operating conditions. A correlation between the surfenergy components and the surface roughness was found. In addition, theoretical models to determine the wettability were included.
We prepared three Al–Mn-based alloys with different copper, magnesium and silicon contents by casting into cylindrical copper molds. All the alloys exhibited primary metastable quasicrystals (QCs). ...In order to confirm the presence of either primary decagonal QCs (dQCs) or icosahedral QCs (iQCs) and to determine their compositions, the castings were characterized by means of light microscopy, scanning electron microscopy, energy-dispersive X-ray spectroscopy (EDS), electron-backscatter diffraction and X-ray diffraction. The dQCs are present in the Al–Mn-based alloys containing copper. In the case of the combined presence of copper and magnesium, iQCs are present in the edge region and dQCs are present in the central region. In the alloy containing copper, magnesium and silicon, iQCs are present in the casting. The average metallic radius (AMR) and electron-to-atom ratio of these primary phases were calculated by taking into account the composition of these primary phases, as determined by EDS. The AMR shows different values in the cases of dQCs and iQCs. Equal mean values of the AMR were found in iQCs with markedly different compositions. Furthermore, all the metastable QCs in this work show electron concentrations close to 2.6.
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DOBA, EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, IZUM, KILJ, KISLJ, MFDPS, NLZOH, NUK, OBVAL, OILJ, PILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, SIK, UILJ, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
0.67Pb(Mg
1/3
Nb
2/3
)O
3
-0.33PbTiO
3
(PMN-33PT) epitaxial thin films were prepared by pulsed-laser deposition (PLD) using ceramic targets, enriched with PbO (and MgO). The phase composition and ...crystal structure were analyzed by high-resolution X-ray diffraction. Accurate chemical analysis of the thin films was carried out using wavelength-dispersive X-ray spectroscopy, which revealed that the target-substrate material transfer is not fully stoichiometric. The largest deviations were found for Pb and Mg content. Our results show that it is possible to effectively tune the stoichiometry of the films
via
the use of custom-made ceramic targets, emphasizing their advantage over single-crystal targets in PLD growth of complex metal oxides. The functional response of the films, however, is the result of complex interactions between the crystal structure, microstructure and chemical composition of the films. Our results show that the sample, prepared from the target with 20 mol% PbO excess, with the largest deviations from the nominal stoichiometry, exhibits the highest longitudinal piezoelectric coefficient.
0.67Pb(Mg
1/3
Nb
2/3
)O
3
-0.33PbTiO
3
(PMN-33PT) epitaxial thin films were prepared by pulsed-laser deposition (PLD) using ceramic targets, enriched with PbO (and MgO).
•B2O3 in Pechini-processed strontium aluminate tunes rare earth dopant partitioning.•SPS freezes in Eu2+, Dy3+ and B concentrations above solubility limits of Sr4Al14O25.•When diffusion is limited, ...Eu Dy concentration exceed solubility limits and segregate to the intergranular phase.•Crystal structure of grains identified by Eu2+ peaks in SEM cathodoluminescence spectra.•4-fold coordinated B appears in Sr4Al14O25 grains exhibiting persistent afterglow.
B has been proposed to extend persistent luminescence from minutes to > 10 h in Eu, Dy, and B co-doped Sr4Al14O25 (S4A7EDB) by facilitating the incorporation of Eu2+ and Dy3+ into adjacent Sr sub-lattice sites and enabling energy transfer between them. To evaluate additional influences of B on the kinetics of microstructural evolution and dopant distribution that support afterglow in S4A7EDB, the effect of heating rates to 1300 °C is compared for spark-plasma sintering and conventional sintering, with and without the addition of B2O3. Analysis of the microstructure and elemental distribution, by a combination of imaging, WDS, and CL in the SEM, XRD, dilatometry, and STEM-EELS, reveals that when the diffusivity of Eu and Dy is increased, Eu and Dy segregate to the intergranular phase. The partitioning of Eu and Dy concentrations to below their solubility limit in the grains appears to be essential to material structure enabling longer afterglow.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
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