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Atomic-scale characteristics of individual nanocrystals (NCs), such as the crystallographic orientation of their facets and the kind and density of crystal structure defects, play a tremendous role for the functionality and performance of the whole NC population. However, these features are usually quantified only for a small number of individual particles, and thus with limited statistical relevance. In the present work, we developed the multiscale approach available in transmission electron microscopy (TEM) further, and applied it to describe features of different types of Au NCs in a statistical and scale-bridging manner. This approach combines high-resolution TEM, which is capable of describing the characteristics of NCs on atomic scale, with a semi-automatic analysis of low-magnification high-angle annular dark-field scanning TEM images, which reveals the nanoscopic morphological attributes of NCs with good statistics. The results of these complementary techniques are combined and correlated. The potential of this multiscale approach is illustrated on two examples. In the first one, the habitus of Au NCs was classified and assigned to multiply twinned nanoparticles and nanoplates. These classes were quantified and related to different stacking fault densities. The second example demonstrates the statistical determination of crystallographic orientations and configurations of facets in Au nanorods.

Sol–gel derived hydroxyapatite coatings on metallic implants are important to promote their osseointegration and biocompatibility. However, such coatings generally suffer from drawbacks that limit implant longevity. In this study, the sol gel process to prepare hydroxyapatite was optimized and used to deposit a hydroxyapatite layer on Ti6Al4V. Samples were pretreated by thermal oxidation, sol–gel coating, and anodization to produce titanium dioxide interlayers with various structures. The results of structural and thermal analysis have determined the optimal preparation parameters to produce monophasic and crystalline hydroxyapatite. The introduction of titanium dioxide intermediate layers produced crack-free hydroxyapatite films and promoted the adherence and integrity of the coating, where the adhesive strength was remarkably improved. Furthermore, potentiodynamic polarization tests in simulated body fluid revealed low corrosion rates and high protection property of the hydroxyapatite/titania coated samples, making these structures promising for the coatings of bone replacements. Graphical abstract

Yb3Co4Ge13 is the first example of a Remeika phase with a 3D + 3 [space group P3n(α,0,0)000(0,α,0)000(0,0,α)000; a = 8.72328(1) A, α = 0.4974(2)] modulated crystal structure. A slight shift of the composition towards higher Yb-content (i.e. Yb3.2Co4Ge12.8) leads to the disappearance of the satellite reflections and stabilization of the disordered primitive cubic [space group Pmn, a = 8.74072(2) A] Remeika prototype structure. The stoichiometric structurally modulated germanide is a metal with hole-like charge carriers, where Yb-ions are in a temperature-dependent intermediate valence state varying from +2.60 to +2.66 for the temperature range 85–293 K. The valence fluctuations have been investigated by means of temperature dependent X-ray absorption spectroscopy, magnetic susceptibility and thermopower measurements.

The effect of the phase composition on the α/β-Ti(Fe)→ω-Ti(Fe) transformation in the Ti-4 wt % Fe alloy under shear strain with high-pressure torsion (HPT) has been studied. For shear deformation by means of HPT, two initial states of the alloy were used, which significantly differed in the morphology of the phases and the concentration of iron atoms in the β phase. During HPT, a stationary state occurred in both sample series, which is characterized by the presence of a single ω phase containing 4 wt % Fe and by a grain size of about 200 nm. Thus, the HPT state is equifinal and independent of the initial phase composition of the samples. It was found that under the influence of HPT in Ti-4 wt % Fe alloys not only martensitic (shear) transformation into the ω phase occurs, but also a significant mass transfer of atoms of the alloying element. An analysis of the change in the torsion torque directly in the HPT process made it possible to estimate the rate of deformation-induced mass transfer. It is 18–19 orders of magnitude higher than the rate of conventional thermal diffusion at the processing temperature THPT = 30°C, while it is close to the diffusivity values at 700–800°C. This is because HPT increases the concentration of lattice defects, which in turn is equivalent to an increase in temperature. A similar combination of accelerated mass transfer during HPT and martensitic (shear) transformation was previously observed in copper-based shape memory alloys, but for the first time studied for the formation of ω-phase in titanium alloys.

In thin amorphous carbon (a-C) films being in contact with a thin nickel layer, metal-induced crystallization and layer exchange (LE) occur at temperatures lower than 700 °C. Analysis of thin film stacks with different architectures (a-C/Ni, Ni/a-C and Ni/a-C/Ni) by means of ion beam analysis, Raman spectroscopy, X-ray diffraction and transmission electron microscopy revealed that the degree of LE and the structural quality of the crystallized carbon layers depend on the initial layer sequence. A LE degree of approx. 93% was found for Ni/a-C bilayers, where graphenic layers formed on the Ni surface, whereas in a-C/Ni bilayers only 83% of carbon was transferred from the surface towards the fused silica substrate. The diffusion of carbon in the outward direction produces turbostratic carbon with basal planes oriented parallel to the Ni surface, while for the inward direction planar and curved turbostratic structures coexist. The crystallization and the LE are driven by the crystallization energy of a-C. The LE is mediated by the wetting of the Ni grain boundaries by carbon. The directionality of the LE was explained primarily by the difference in the surface and interface energies in the a-C/Ni and Ni/a-C stacks that were obtained from thermodynamic considerations.

Self-assembly is an attractive phenomenon that, with proper handling, can enable the production of sophisticated hybrid nanostructures with sub-nm-scale precision. The importance of this phenomenon is particularly notable in the fabrication of metal–organic nanomaterials as promising substances for spintronic devices. The exploitation of self-assembly in nanofabrication requires a comprehension of atomic processes creating hybrid nanostructures. Here, we focus on the self-assembly processes in the vapour-deposited AuxC60 mixture films, revealing the exciting quantum plasmon effects. Through a systematic characterization of the AuxC60 films carried out using structure-sensitive techniques, we have established correlations between the film nanostructure and the Au concentration, x. The analysis of these correlations designates the Au intercalation into the C60 lattice and the Au clustering as the basic processes of the nanostructure self-assembly in the mixture films, the efficiency of which strongly depends on x. The evaluation of this dependence for the AuxC60 composite nanostructures formed in a certain composition interval allows us to control the size of the Au clusters and the intercluster spacing by adjusting the Au concentration only. This study represents the self-assembled AuxC60 mixtures as quantum materials with electronic functions tuneable by the Au concentration in the depositing mixture.

The dynamic recrystallization and changes in the preferred orientation of crystallites during hot rolling at 500 °C have been studied on a cast Mg-6.8Y-2.5Zn-0.3Zr (wt. %) alloy (WZ73) containing long-period stacking ordered (LPSO) phases. The recrystallization began predominantly within twins and also occurred near the LPSO phases. The twinned regions have a much higher stored strain energy compared to the matrix, and are therefore favorable nucleation sites for dynamic recrystallization. Besides, the bits of the LPSO phase located at the grain boundaries of the magnesium matrix grains act as nucleation sites for dynamic recrystallization. With increasing strain from 36 % to 74 %, the average volume fraction of recrystallized grains increased from 3.5 % to 48.8 %. The intensive recrystallization process resulted in basal texture weakening. Thus, the resulting microstructure is a mixture of randomly oriented, dynamically recrystallized and coarse, highly oriented non-recrystallized grains.

Marine sponges were among the first multicellular organisms on our planet and have survived to this day thanks to their unique mechanisms of chemical defense and the specific design of their skeletons, which have been optimized over millions of years of evolution to effectively inhabit the aquatic environment. In this work, we carried out studies to elucidate the nature and nanostructural organization of three-dimensional skeletal microfibers of the giant marine demosponge Ianthella basta, the body of which is a micro-reticular, durable structure that determines the ideal filtration function of this organism. For the first time, using the battery of analytical tools including three-dimensional micro—X-ray Fluorescence (3D-µXRF), X-ray diffraction (XRD), infra-red (FTIR), Raman and Near Edge X-ray Fine Structure (NEXAFS) spectroscopy, we have shown that biomineral calcite is responsible for nano-tuning the skeletal fibers of this sponge species. This is the first report on the presence of a calcitic mineral phase in representatives of verongiid sponges which belong to the class Demospongiae. Our experimental data suggest a possible role for structural amino polysaccharide chitin as a template for calcification. Our study suggests further experiments to elucidate both the origin of calcium carbonate inside the skeleton of this sponge and the mechanisms of biomineralization in the surface layers of chitin microfibers saturated with bromotyrosines, which have effective antimicrobial properties and are responsible for the chemical defense of this organism. The discovery of the calcified phase in the chitinous template of I. basta skeleton is expected to broaden the knowledge in biomineralization science where the calcium carbonate is regarded as a valuable material for applications in biomedicine, environmental science, and even in civil engineering.

Yb

In recent years, nanolamellar aluminum-rich face-centered cubic (fcc) Ti1-xAlxN coatings with x as high as 0.8–0.9 grown by thermal chemical vapor deposition (CVD) have been investigated extensively. However, detailed information about their microstructure characteristics, local chemical composition and phase stability at elevated temperatures is still missing. Thus, within the present work, the temperature-induced microstructural changes of a nanolamellar fcc-Ti0.2Al0.8N coating, synthesized by thermal CVD at ∼790 °C, were studied up to temperatures of 1300 °C. In situ high-temperature X-ray powder diffraction and differential scanning calorimetry were employed to follow the phase evolution at elevated temperatures. Scanning electron microscopy and electron backscatter diffraction, carried out ex situ for six different microstructural states after isothermal annealing, revealed the distribution of individual phases and morphology of different phase regions. Complementary atom probe tomography as well as transmission electron microscopy experiments were performed on the as-deposited, an intermediate and the final decomposed and transformed state. The results provided 3D elemental information as well as detailed morphology, phase and orientation information of the respective samples. In the as-deposited state, the coating was characterized by columnar, relatively large fcc grains exhibiting a nanolamellar microstructure. Decomposition of initially supersaturated fcc-Ti1-xAlxN was detected at temperatures of ∼900–1000 °C. Transformation of metastable Al-rich fcc regions into the thermodynamically stable wurtzitic modification started at ∼1000 °C and persisted up to ∼1175 °C. In this temperature range, intact nanolamellar fcc areas coexisted with fully decomposed and transformed regions, leading to a constant reduction of the fcc fraction with increasing temperature. At temperatures above ∼1175 °C, the coating was fully decomposed and transformed into fcc-TiN and w-AlN. The obtained findings provide a detailed description of the decomposition and transformation behavior of nanolamellar CVD fcc-Ti1-xAlxN coatings, which significantly contributes to the fundamental understanding of this complex coating system.

Three types of hexagonal boron nitride (h-BN) with graphitic crystal structure having different microstructures were subjected to high pressures (HP) and high temperatures (HT), and the kinetics of the phase transitions to the sp3-hybridized phases (w-BN, c-BN) was studied using in situ synchrotron diffraction. The analysis of the phase transformation kinetics revealed the transformation paths and activation energies Ea of the transformation of h-BN to the high-pressure forms of BN for different microstructures of h-BN. Defect-poor h-BN transforms to metastable wurtzitic BN (w-BN) with Ea ≈ 0.3 eV/at. Defect-rich forms of h-BN transform directly to c-BN, but with a higher activation energy. It was observed that the turbostratic disorder in h-BN retards the phase transition as compared to h-BN containing corrugated basal planes and a low degree of turbostracity. The experimental results are discussed in view of the microstructure changes during the HP/HT treatment and compared to available theoretical phase transition models.

In the present work an azomethinic pincer ( P ) possessing an ONNNO donor set was prepared via condensation reaction of diethylenetriamine and o -hydroxyacetophenone followed by silyl-functionalization (introduction of a triethoxysilylpropyl or silatranylpropyl group via urea linker) to afford P-Sil and P-Silt , respectively. The resulting products were characterized by various spectroscopic techniques, elemental analysis and single-crystal X-ray diffraction. They were further utilized for the fabrication of post-synthesis functionalized mesoporous silica nanoparticles (MSNs) using similar reaction conditions. The obtained hybrid materials (P-Sil@MSNs and P-Silt@MSNs) were characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), thermogravimetry (TGA), nitrogen gas adsorption-desorption measurements and C,H,N microanalysis. The corresponding results revealed particularly high loading of organic moieties for the P-Silt functionalized particles. In addition, adsorption behavior of both materials towards the anionic dye eriochrome black T (EBT) was evaluated by examining the effect of pH, solution temperature, time and dye concentration. The maximum adsorption capacity of P-Silt@MSNs and P-Sil@MSNs at pH = 3 was found to be 101 mg g −1 and 69.9 mg g −1 , respectively (calculated on the basis of Langmuir model). The characterization and adsorption studies revealed better loading of organic moieties in P-Silt@MSNs with respect to P-Sil@MSNs. Furthermore, P-Silt@MSNs was used to adsorb the cationic dye methylene blue (MB) at pH = 8. Its maximum adsorption capacity reached 28 mg g −1 .

The aim of the study was the synthesis of multifunctional TiO2-ZnO oxide systems with desired antibacterial and photocatalytic activity. It was investigated how the TiO2:ZnO molar ratio and the time of hydrothermal treatment affected the physicochemical and structural properties (including morphology, crystalline and porous structure, as well as chemical surface composition) of the synthesized materials. For the first time this type of binary oxide systems were used as antibacterial materials against Gram-positive, Gram-negative and anaerobic bacteria. Moreover, the photocatalytic properties of the obtained materials were verified in the degradation of C.I. Basic Violet 10 dye. The SEM analysis demonstrates that binary oxide materials based on TiO2 and ZnO were found to have spherically and hexagonally shaped particles, characteristic of both oxides. The results of XRD, Raman and HRTEM analysis proved that the molar ratio of the components affects the crystalline structure of the synthesized oxide materials. Analysis of porous structure parameters showed that an increase in the ZnO content leads to a decrease in the BET surface area. Moreover, low-temperature N2 sorption analysis demonstrates that TiO2-ZnO oxide systems have higher surface are than the pure oxides. The TiO2-ZnO oxide systems exhibited very good antibacterial activity against Gram-positive bacteria, especially Staphylococcus aureus (including methicillin-resistant Staphylococcus aureus). The photo-oxidation tests proved that the binary oxide materials (especially the T9Zn1 samples) demonstrates high photocatalytic activity in the decomposition of C.I. Basic Violet 10 (95% after 180 min irradiation) compared with the reference titania sample.

The defect structure of γ-Al2O3 produced from boehmite is described with the aid of antiphase and rotational boundaries. The type of structure defects is deduced from the selected-area electron-diffraction patterns. The defect density is quantified from the anisotropic broadening of diffraction lines in powder X-ray diffraction patterns using a computer routine based on the Debye scattering equation., The defect structure of γ-Al2O3 derived from boehmite was investigated using a combination of selected-area electron diffraction (SAED) and powder X-ray diffraction (XRD). Both methods confirmed a strong dependence of the diffraction line broadening on the diffraction indices known from literature. The analysis of the SAED patterns revealed that the dominant structure defects in the spinel-type γ-Al2O3 are antiphase boundaries located on the lattice planes , which produce the sublattice shifts . Quantitative information about the defect structure of γ-Al2O3 was obtained from the powder XRD patterns. This includes mainly the size of γ-Al2O3 crystallites and the density of planar defects. The correlation between the density of the planar defects and the presence of structural vacancies, which maintain the stoichiometry of the spinel-type γ-Al2O3, is discussed. A computer routine running on a fast graphical processing unit was written for simulation of the XRD patterns. This routine calculates the atomic positions for a given kind and density of planar defect, and simulates the diffracted intensities with the aid of the Debye scattering equation.

Hematite (alpha-Fe2O3) catalysts prepared using the precipitation methods was found to be highly effective, and therefore, it was studied with methane (CH4), showing an excellent stable performance below 500 degrees C. This study investigates hematite nanoparticles (NPs) obtained by precipitation in water from the precursor of ferric chloride hexahydrate using precipitating agents NaOH or NH4OH at maintained pH 11 and calcined up to 500 degrees C for the catalytic oxidation of low concentrations of CH4 (5% by volume in air) at 500 degrees C to compare their structural state in a CH4 reducing environment. The conversion (%) of CH4 values decreasing with time was discussed according to the course of different transformation of goethite and hydrohematites NPs precursors to magnetite and the structural state of the calcined hydrohematites. The phase composition, the size and morphology of nanocrystallites, thermal transformation of precipitates and the specific surface area of the NPs were characterized in detail by X-ray powder diffraction, transmission electron microscopy, infrared spectroscopy, thermal TG/DTA analysis and nitrogen physisorption measurements. The results support the finding that after goethite dehydration, transformation to hydrohematite due to structurally incorporated water and vacancies is different from hydrohematite alpha-Fe2O3. The surface area SBET of Fe2O3_NH-70 precipitate composed of protohematite was larger by about 53 m(2)/g in comparison with Fe2O3_Na-70 precipitate composed of goethite. The oxidation of methane was positively influenced by the hydrohematites of the smaller particle size and the largest lattice volume containing structurally incorporated water and vacancies. Web of Science 23 15 art. no. 8163

Rutile coatings deposited on corundum substrates are considered as promising functional elements improving the efficiency of the filtration of oxide inclusions out of aluminium melts. This contribution describes the reactions between rutile and two kinds of the aluminium melts and discusses the consequences of these reactions for the filtration process. It was found that the contact of rutile coatings with molten aluminium leads to the formation of a corundum layer at the solid/liquid interface. The exposure of the rutile coatings to molten AlSi7Mg0.6 alloy produces an interface layer of MgTiO3. The interface layers possess defined orientation relationship to rutile which is characteristic for locally heteroepitaxial growth. The density functional theory calculations revealed that the TiO2/α-Al2O3 and TiO2/MgTiO3 interfaces with the orientation relationships observed experimentally have low interface energies. The mechanisms of the interface layer formation and the impact of these layers on the degradation of the rutile coatings are discussed.

The design of new composite materials using extreme biomimetics is of crucial importance for bioinspired materials science. Further progress in research and application of these new materials is impossible without understanding the mechanisms of formation, as well as structural features at the molecular and nano-level. It presents a challenge to obtain a holistic understanding of the mechanisms underlying the interaction of organic and inorganic phases under conditions of harsh chemical reactions for biopolymers. Yet, an understanding of these mechanisms can lead to the development of unusual—but functional—hybrid materials. In this work, a key way of designing centimeter-scale macroporous 3D composites, using renewable marine biopolymer spongin and a model industrial solution that simulates the highly toxic copper-containing waste generated in the production of printed circuit boards worldwide, is proposed. A new spongin–atacamite composite material is developed and its structure is confirmed using neutron diffraction, X-ray diffraction, high-resolution transmission electron microscopy/selected-area electron diffraction, X-ray photoelectron spectroscopy, near-edge X-ray absorption fine structure spectroscopy, and electron paramagnetic resonance spectroscopy. The formation mechanism for this material is also proposed. This study provides experimental evidence suggesting multifunctional applicability of the designed composite in the development of 3D constructed sensors, catalysts, and antibacterial filter systems.

The size fractionation of magnetic nanoparticles is a technical problem, which until today can only be solved with great effort. Nevertheless, there is an important demand for nanoparticles with sharp size distributions, for example for medical technology or sensor technology. Using magnetic chromatography, we show a promising method for fractionation of magnetic nanoparticles with respect to their size and/or magnetic properties. This was achieved by passing magnetic nanoparticles through a packed bed of fine steel spheres with which they interact magnetically because single domain ferro-/ferrimagnetic nanoparticles show a spontaneous magnetization. Since the strength of this interaction is related to particle size, the principle is suitable for size fractionation. This concept was transferred into a continuous process in this work using a so-called simulated moving bed chromatography. Applying a suspension of magnetic nanoparticles within a size range from 20 to 120 nm, the process showed a separation sharpness of up to 0.52 with recovery rates of 100%. The continuous feed stream of magnetic nanoparticles could be fractionated with a space-time-yield of up to 5 mg/(L∙min). Due to the easy scalability of continuous chromatography, the process is a promising approach for the efficient fractionation of industrially relevant amounts of magnetic nanoparticles.

Materials characterization 176(111132), 1-14 (2021). doi:10.1016/j.matchar.2021.111132, The interplay of microstructural mechanisms controlling the deformation-induced martensitic phase transformationsand the texture formation in all phases of a metastable austenitic Cr-Mn-Ni steel was investigatedusing in situ synchrotron radiation diffraction under uniaxial compression and ex situ electron backscatterdiffraction. With increasing deformation, the originally fully austenitic steel transformed to a mixture ofγ-austenite, ε-martensite and α´-martensite. The face centred cubic γ-austenite formed a fibre texture {110} withrespect to the deformation direction. The texture degree increased progressively with increasing deformation.The hexagonal close packed ε-martensite was preferentially oriented with the reciprocal direction {1013} alongthe load axis. The texture degree was nearly independent of the deformation extent. The body centredα´-martensite formed a mixed texture {100} & {111} along the deformation direction. The texture component{100} was very strong in the early stages of the α´-martensite formation, but it deteriorated with increasingdeformation. The texture evolution is explained by the competition between the transformation texture, severaldeformation-induced mechanisms, which are highly sensitive to the local orientation of the grains with respect tothe acting force, like the stacking fault formation and martensitic transformation in austenite, and the variantselection in both martensites and the twinning of α´-martensite., Published by Science Direct, New York, NY

Selected hypermineralized bones (rostrum and tympanic bullae) have yet to be characterized for diverse species of whales (Cetacea). Hypermineralization in these structures is an example of extreme biomineralization that, however, occurs at temperatures around 36 °C. In this study we present the results of analytical investigations of the specimen of tympanic bulla isolated from gray whale (Eschrichtius robustus) for the first time. Examination of the internal surface of the bone mechanically crushed under a press revealed the presence of a lipid-containing phase, which did not disappear even after complete demineralization of the bone material. Additionally, analytical investigations including CARS, ATR-FTIR, Raman and XRD confirmed the presence of carbonated bioapatite and a collagen- lipid complex as the main components of this up to 2.34 kg/cm3 dense bone. Our experimental results open the way for further research on understanding of the principles of hypermineralization in highly specialized whale bones.

Large-scale nonequilibrium molecular dynamics (MD) simulations of shock waves in nanocrystalline iron show evidence of plasticity before the polymorphic transformation takes place. The atomistic structure in the shock direction shows an elastic precursor, plastic deformation, and shock-induced phase transformation from bcc to hcp iron. In this Rapid Communication, large-scale MD models show that the shock response of iron is highly related to the ramp time of the applied shocks. For long ramp times we observe significant plastic relaxation and formation of microstructure defects. Pressure-induced phase transformations in iron are accompanied by stress relaxation achieving almost fully relaxed three-dimensional hydrostatic final states. The evolution of the stress relaxation is in agreement with theory and experiments. Analysis of the x-ray diffraction patterns calculated from the atomistic structure using the Debye equation revealed pronounced anisotropy of the line broadening that is caused by stacking faults in hcp Fe and by dislocations in bcc Fe.

Chitin, as one of nature&rsquo, s most abundant structural polysaccharides, possesses worldwide, high industrial potential and a functionality that is topically pertinent. Nowadays, the metallization of naturally predesigned, 3D chitinous scaffolds originating from marine sponges is drawing focused attention. These invertebrates represent a unique, renewable source of specialized chitin due to their ability to grow under marine farming conditions. In this study, the development of composite material in the form of 3D chitin-based skeletal scaffolds covered with silver nanoparticles (AgNPs) and Ag-bromide is described for the first time. Additionally, the antibacterial properties of the obtained materials and their possible applications as a water filtration system are also investigated.