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CdS nanoparticles were successfully synthesized using cadmium acetate and sodium sulfide as Cd and S precursors, respectively. The effect of using sodium thiosulfate as an additional sulfur precursor was also investigated (combined milling). The samples were characterized by XRD, Raman spectroscopy, XPS, UV-Vis spectroscopy, PL spectroscopy, DLS, and TEM. Photocatalytic activities of both CdS samples were compared. The photocatalytic activity of CdS, which is produced by combined milling, was superior to that of CdS, and was obtained by an acetate route in the degradation of Orange II under visible light irradiation. Better results for CdS prepared using a combined approach were also evidenced in photocatalytic experiments on hydrogen generation. The antibacterial potential of mechanochemically prepared CdS nanocrystals was also tested on reference strains of E. coli and S. aureus. Susceptibility tests included a 24-h toxicity test, a disk diffusion assay, and respiration monitoring. Bacterial growth was not completely inhibited by the presence of neither nanomaterial in the growth environment. However, the experiments have confirmed that the nanoparticles have some capability to inhibit bacterial growth during the logarithmic growth phase, with a more substantial effect coming from CdS nanoparticles prepared in the absence of sodium thiosulfate. The present research demonstrated the solvent-free, facile, and sustainable character of mechanochemical synthesis to produce semiconductor nanocrystals with multidisciplinary application. [ABSTRACT FROM AUTHOR]

A number of nanocomposite titanium carbohydrides are prepared via high-energy mechanosynthesis in liquid hydrocarbons (n-heptane and toluene) using a planetary ball mill. X-ray diffraction analysis reveals that at the initial stages of mechanochemical treatment titanium powder consists of a mixture of fcc and hcp phases with different contents of carbon and hydrogen. The composites become monophasic after 15 h of mechanosynthesis in both heptane and toluene as a result of the hcp → fcc structural phase transition. Differential scanning calorimetry and thermal desorption are used to perform a comparative analysis of thermally-induced hydrogen desorption in powder samples prepared in heptane and toluene with different synthesis time. Experimental evidence shows that thermally stable titanium carbohydrides and carbides can be obtained at prolonged synthesis time, with their chemical composition and rate of formation depending on the medium used in mechanosynthesis. [ABSTRACT FROM AUTHOR]

We apply high energy mechanosynthesis in mixtures of Y2O3 and Fe2O3 to form activated nanostructured oxide composites for subsequent temperature treatment with the aim to synthesize single phase functional Y3Fe5O12 garnet particles. Obtained at the same temperature regime but starting from structurally different precursors, garnet particles demonstrate different magnetic behavior. Mossbauer and Raman spectroscopy were applied for a comprehensive characterization on the local atomic scale the influence of the mechanochemically produced precursor's fine structure formed at different activation duration on the structural and magnetic state of the garnet particles. X-ray diffraction and visualization of fine particles structure by SEM microscopy were supplemented. An intermediate disordered iron oxide phases and orthoferrite YFeO3 rather garnet structure formation at prolonged duration of intense mechanical activation was determined. Magnetic structure of Y3Fe5O12 formed after annealing was dependent on the degree of the oxides interaction in precursors and defects concentrated at the grain boundaries and interfaces. Both applied spectroscopies showed complementary insight into the nature of the local structural disorder at the steps of mechanosynthesis to the mechanism of fine garnet structure formation. [ABSTRACT FROM AUTHOR]

The mechanically assisted synthesis of organic compounds has recently focused considerable attention as it may be unique in features to selectively direct the reaction pathway. In the continuation of our work on the synthesis of modified cyclodextrins (CDs) via mechanochemical activation, we sought to discriminate the contribution of supramolecular effects and grinding during the course of a reaction in the solid state. As such, we recently investigated the influence of the particle size of β-CD in the synthesis of β-CD mesitylene sulfonate (β-CDMts) in the solid state using a vibrating ball-mill. We were particularly interested in the role of the particle size on the kinetics of the reaction. In this study, we show that grinding β-CD reduces the particles size over time down to a limit of 167 nm. The granulometric composition remains rather invariant for grinding times over 1 h. Each type of β-CD particles reacted with mesitylenesulfonyl chloride (MtsCl) to produce β-CDMts. Contrary to what could be intuitively anticipated, smaller particles did not lead to the highest conversions. The impact of grinding on the conversion was limited. Interestingly, the proportion of β-CDMts mono-substituted on the primary face significantly increased over time when the reaction was carried out in the presence of KOH as a base. The data series were confronted with kinetics models to get insight in the way the reactions proceeded. The diversity of possible models suggests that multiple mechanochemical processes can account for the formation of β-CDMts in the solid state. Throughout the study, we found that the reactivity depended more upon diffusion phenomena in the crystalline parts of the material than on the increase in the surface area of the CD particles resulting from grinding.

Температурна обробка сумішей рідкісноземельних оксидів (РЗО) широко застосовується для створення різних функціональних матеріалів технічного призначення та дає змогу отримати матеріали із наперед заданими властивостями. За допомогою методів рентгенофазового аналізу (РФА) та електронного парамагнітного резонансу (ЕПР) проведено вивчення процесу структуроутворення при термічній обробці гомогенізованої механохімічним методом подвійної суміші діоксиду церію (5 мол. %) та оксиду ітербію (95 мол %) за температур 120, 1100 та 1500 °С. Встановлено зміну фазового складу і структури кераміки на основі CeO2 і Yb2O3 при збільшені температури та тривалості прожарювання. В гетерогенному складі зразка, отриманого після термообробки за Т = 1500 °С впродовж 50 год, доведено наявність впорядкованої фази типу перовскіту CeYbO3. На спектрах ЕПР продемонстровано вплив температурної обробки зразків у діапазоні від 120 до 1500 °С на інтенсивність, форму та положення спектральних ліній, значення g-фактору. Встановлено, що термообробка суміші призводить до зміни спектральних ЕПР характеристик і властивостей оксидів церію та ітербію. На підставі даних ЕПР проведено інтерпретацію фізичних і хімічних змін складових суміші (оксидів РЗЕ в заданому молярному співвідношенні) при її обробці в зазначеному інтервалі температур. Встановлено, що на утворення впорядкованої фази типу перовскіту впливає не тільки підвищення температури, але і тривалість термічної обробки. Показано, що за всіх режимів термообробки зразка домінуючою є кубічна фаза С-Yb2O3.

In this work, we reported obtaining mesoporous Bi-doped TiO2 by mechanosynthesis and bismuth loading of 0%, 1%, 3%, 5%, and 10% (milled TiO2, TiO2 Bi 1%, TiO2 Bi 3% TiO2 Bi 5%, and TiO2 Bi 10%, respectively). The effect of bismuth doping and ball milling on the crystal structure, optical properties, and photocatalytic performance of Bi-doped TiO2 mesoporous samples under UV, visible, and sun irradiation was investigated. According to the results of the Rietveld refinement, the estimated chemical formulas for the TiO2 Bi 1%, TiO2 Bi 3%, TiO2 Bi 5%, and TiO2 Bi10% samples were Ti0.99Bi0.01O2, Ti0.97Bi0.03O2, Ti0.96Bi0.04O2, and Ti0.91Bi0.09O2 respectively. The incorporation of Bi into the TiO2 lattice causes the crystallite size to decrease and, consequently, the absorption spectrum of TiO2 to extend into the visible region of the electromagnetic spectrum, resulting in a lower band gap (Eg) value. Bi-doped TiO2 mesoporous samples had Eg values of 2.90 eV, 2.83 eV, 2.77 eV, and 2.70 eV for the TiO2 Bi 1%, TiO2 Bi 3%, TiO2 Bi 5%, and TiO2 Bi 10% samples, respectively. Photocatalytic removal of methylene blue (MB) data fit well for second-order kinetics. Photocatalytic activity increase followed the order of TiO2 Bi 5% > TiO2 Bi 10% > TiO2 Bi 3% > TiO2 Bi 1% > pristine TiO2. The TiO2 Bi 5% sample exhibited excellent photocatalytic performance for MB photodegradation under natural sunlight (89.2%).

Low temperature magnetic properties of BiFeO3 powders sintered by flash and spark plasma sintering were studied. An anomaly observed in the magnetic measurements at 250 K proves the clear existence of a phase transition. This transformation, which becomes less well-defined as the grain sizes are reduced to nanometer scale, was described with regard to a magneto-elastic coupling. Furthermore, the samples exhibited enhanced ferromagnetic properties as compared with those of a pellet prepared by the conventional solid-state technique, with both a higher coercivity field and remnant magnetization, reaching a maximum value of 1.17 kOe and 8.5 10−3 emu/g, respectively, for the specimen sintered by flash sintering, which possesses the smallest grains. The specimens also show more significant exchange bias, from 22 to 177 Oe for the specimen prepared by the solid-state method and flash sintering technique, respectively. The observed increase in this parameter is explained in terms of a stronger exchange interaction between ferromagnetic and antiferromagnetic grains in the case of the pellet sintered by flash sintering.

[Display omitted] • Mechanosynthesis of hydroxyfluorapatite powder. • Nanoparticles are characterised by XRD, IR, Raman, DLS, BET, SEM, XPS and TEM. • A mathematical model is introduced to analyze the effect of milling parameters. • Experimental results are in agreement with the calculations of the theorical model. • The resulting hydroxyfluorapatite powder exhibits an average grain size of about 10 nm. The nanocrystalline hydroxyfluorapatite (HFA) was synthesized by mechanosynthesis with a planetary ball mill (PM200). The disc to jar speed ratio was constant (equal to 0.5). The effect of different milling parameters such as grinding duration, balls number's, initial powder mass and disc rotation speed were studied to apprehend their effects on both the process of grinding/mechanosynthesis and the synthesis of nanocrystalline HFA. Unlike previous studies in which milling parameters have been independently studied, the effects of these parameters on the phase contents were simultaneously studied. Abdellaoui's model was also introduced to analyse the physical milling parameters effect such as the injected shock power, the shock kinetic energy, the shock frequency and the cumulated kinetic energy on the microstructural properties and synthesized phases contents. The results predicted by the model were compared to experimental ones. This study showed that the optimal conditions for the synthesis of nanocrystalline HFA were reached when the mechanosynthesis was carried out with a speed of 450 rpm, 6 balls, 1.2 g of starting material and 24 h of grinding duration. X-ray diffraction characterization confirmed the purity phase of HFA nanocrystalline powders. [ABSTRACT FROM AUTHOR]

Comparative studies of the iron–75fullerite and iron–75graphite composites obtained by the mechanosynthesis method have been performed by X-ray diffraction and Mössbauer spectroscopy. It has been shown that a carbon polymorph and its deformation stability predetermine the kinetics of formation for the phase composition of composites. In the case of disordering in the crystal structure of fullerite with the further destruction of fullerene molecules, iron–75fullerite powders are characterized by the same phase composition as for the iron–75graphite composite: amorphous carbon, Fe3C, Fe7C3, and the P-phase. [ABSTRACT FROM AUTHOR]

Formation of phases in nanocomposites of composition of carbide steels alloyed with chromium and nickel obtained as a result of mechanosynthesis in a planetary ball mill and further annealing was studied. It was shown that the structure mainly consisting of nickel-alloyed austenite and chromium-alloyed cementite is realized in composite (Fe0.80Cr0.10Ni0.10)83C17 after annealing at temperatures of 700–800°C. The size of cementite grains is in the nanometer range. [ABSTRACT FROM AUTHOR]

Composite materials based on ultrahigh molecular weight polyethylene (UHMWPE) and magnesium ferrite particles—precursors for future formation of light protective material against electromagnetic radiation—have been synthesized mechanochemically. By application of scanning electron microscopy, X‑ray diffraction, differential scanning calorimetry, and magnetic measurements, the influence of the methods of synthesizing ferrite particles (solid phase, coprecipitation, sol–gel, or mechanosynthesis) on the structural and morphological characteristics of UHMWPE/ferrite composite materials has been studied. It is shown that the mechanochemical method of composite formation contributes to as an increase in the dispersity ferrite particles, by their nonuniform distribution in the UHMWPE volume with the transformation of its supramolecular structure. The method of synthesizing ferrite particles has a different effect on the formation of the molecular structure of UHMWPE: the appearance of a larger number of molecular structures with low melting points was a sign of greater homogeneity of mixing using smaller and uniform particles of ferrite. The observed formation of low molecular weight polymer chains should increase the rate of mutual diffusion between the boundaries of the polymer particles, which in sintering processes will lead to better sintering of the particles. [ABSTRACT FROM AUTHOR]

Skin cancer is a frequent neoplasm in Brazil and this, is observed the importance of the development of new sunscreens using simple methodologies capable of reducing production costs. In this context, six symmetric acyclic azines were synthesized and characterized, with reaction yields between 54 and 84%, short reaction times (5 to 10 min), and manual grinding as an energy source. Sunscreens 10 %(m/m) of these compounds were produced for the in vitro determination of the solar protection factor UVB (SPF-UVB), of the the six formulations containing the synthesized azines, four showed higher photoprotective capacity in the UVB region (AZN-BZD, AZN-2OH, AZN-4OH and AZN-CIN), with SPF-UVB equivalent or higher than benzophenone-3 (BZF) and at the octylmethoxycinnamate (OMC), commercial chemical filters. The AZN-VAN and AZN-4DAB formulations presented high photoprotective capacity in the UVA region, resulting in lower SPF-UVB when compared to the other synthesized azines, but were still superior to the BZF and equivalent to the OMC. All the azines synthesized showed superior FPS-UVB to their precursor aldehydes, evidencing the increase of the photoprotective capacity due to the insertion of the azine group.

The application of polymers to replace oleylamine (OLA) and oleic acid (OA) as ligands for perovskite nanocrystals is an effective strategy to improve their stability and durability especially for the solution-based processing. Herein, we report a mechanosynthesis of lead bromide perovskite nanoparticles (NPs) stabilized by partially hydrolyzed poly(methyl methacrylate) (h-PMMA) and high-molecular-weight highly-branched poly(ethylenimine) (PEI-25K). The as-synthesized NP solutions exhibited green emission centered at 516 nm, possessing a narrow full-width at half-maximum of 17 nm and as high photoluminescence quantum yield (PL QY) as 85%, while showing excellent durability and resistance to polar solvents, e.g., methanol. The colloids of polymer-stabilized NPs were directly processable to form stable and strongly-emitting thin films and solids, making them attractive as gain media. Furthermore, the roles of h-PMMA and PEI-25K in the grinding process were studied in depth. The h-PMMA can form micelles in the grinding solvent of dichloromethane to act as size-regulating templates for the growth of NPs. The PEI-25K with large amounts of amino groups induced significant enrichment of PbBr2 in the reaction mixture, which in turn caused the formation of CsPb2Br5-mPbBr2 and CsPbBr3-Cs4PbBr6-nCsBr NPs. The presence of CsPbBr3-Cs4PbBr6-nCsBr NPs was responsible for the high PL QY, as the Cs4PbBr6 phase with a wide energy bandgap can passivate the surface defects of the CsPbBr3 phase. This work describes a direct and facile mechanosynthesis of polymer-coordinated perovskite NPs and promotes in-depth understanding of the formation and phase conversion for perovskite NPs in the grinding process. [ABSTRACT FROM AUTHOR]

CdS nanoparticles were successfully synthesized using cadmium acetate and sodium sulfide as Cd and S precursors, respectively. The effect of using sodium thiosulfate as an additional sulfur precursor was also investigated (combined milling). The samples were characterized by XRD, Raman spectroscopy, XPS, UV-Vis spectroscopy, PL spectroscopy, DLS, and TEM. Photocatalytic activities of both CdS samples were compared. The photocatalytic activity of CdS, which is produced by combined milling, was superior to that of CdS, and was obtained by an acetate route in the degradation of Orange II under visible light irradiation. Better results for CdS prepared using a combined approach were also evidenced in photocatalytic experiments on hydrogen generation. The antibacterial potential of mechanochemically prepared CdS nanocrystals was also tested on reference strains of E. coli and S. aureus. Susceptibility tests included a 24-h toxicity test, a disk diffusion assay, and respiration monitoring. Bacterial growth was not completely inhibited by the presence of neither nanomaterial in the growth environment. However, the experiments have confirmed that the nanoparticles have some capability to inhibit bacterial growth during the logarithmic growth phase, with a more substantial effect coming from CdS nanoparticles prepared in the absence of sodium thiosulfate. The present research demonstrated the solvent-free, facile, and sustainable character of mechanochemical synthesis to produce semiconductor nanocrystals with multidisciplinary application.

Mechanochemical synthesis of CsPbI3, as a model system for ABX3 halides, was studied. Water was shown to strongly promote the kinetics of formation of CsPbI3 from the CsI+PbI2 mixture through increased mobility of the constituting ionic species. Since many binary and ternary halides are hygroscopic, it was concluded that the presence of small, uncontrollable and unintentional additions of water should often occur in both precursor mixtures and synthesized complex halides boosting the kinetics of formation of many, if not all, ternary organic–inorganic hybrid halides such as, for example, MAPbX3 (X=Cl, Br, I). In addition, trace amounts of water should influence the transport characteristics of complex halides. Thus, the presence of water explains, at least partially, the huge scatter in both the reported mechanochemical reaction times necessary for obtaining single‐phase APbX3 perovskite halides and the activation energies of ionic diffusion in APbX3. [ABSTRACT FROM AUTHOR]

The six possible equiatomic five-transition metal High Entropy Carbides (HECs) of the IVB (Ti, Zr, Hf) and VB (V, Nb, Ta) groups of the periodic table, i.e., TiZrHfVNbC 5 , TiZrHfVTaC 5 , TiZrHfNbTaC 5 , TiZrVNbTaC 5 , TiHfVNbTaC 5 and ZrHfVNbTaC 5 , were successfully obtained via a powder metallurgy route at room temperature, specifically, by one-step diffusion mechanosynthesis starting from the elemental constituents (using graphite as the carbon source). Three of those HECs, TiZrHfVTaC 5 , TiZrVNbTaC 5 and ZrHfVNbTaC 5 , were developed for the first time. Their development was possible without any subsequent thermal treatment, in contrast to the usual way (reactive sintering at 1800–2200 °C), and in a powder form, make them potential advanced raw ceramics for hard, refractory and oxidation resistance coatings or matrix phase composites. [ABSTRACT FROM AUTHOR]

We performed a one‐pot mechanosynthesis of adaptive conducting gels using carbon nanotubes (CNTs) and a non‐volatile eutectic liquid (EL) of diphenylamine (DP) with benzophenone (BP). Upon further mixing with ammonium persulfate (APS), oxidative polymerization of DPs enabled the generation of electrically healable conductors containing poly(diphenylamine) (PDPA) as an adaptive matrix. The resulting composite gels were created through a synergistic combination of CNTs and PDPAs, which exhibited printable and conductive characteristics. Thus, after printing on an elastic substrate, the conducting ink composite displayed excellent electromechanical sensory properties. [ABSTRACT FROM AUTHOR]

Solid-state compatibility of API with excipients is essential step in the preformulation stage of early development of new finished dosage form. Thermal analysis and vibrational spectroscopy are complementary techniques that play a pivotal role to assess the solid-state compatibility of API with excipients. Their coupling and combination with multivariate analysis, provide valuable quantitative aspect to reveal the potential interactions. The impetus of this work was aimed to fully elucidate the solid-state compatibility of ibuprofen and magnesium stearate in binary mixtures comprising pharmaceutically acceptable amounts of magnesium stearate (0.25–5% w/w). Binary mixtures were analyzed before and after exposure at strictly controlled stress conditions (25 °C/60% relative humidity and 40 °C/75% relative humidity). Interaction between ibuprofen and magnesium stearate was unambiguously confirmed. The product of their interaction was synthetized separately, characterized by means of FTIR spectroscopy, DSC, TG/DTG and XRPD for the first time and identified as diibuprofen magnesium. The induced solid-state pseudopolymorphic transition of this product to diibuprofen magnesium tetrahydrate was also studied and discussed. [ABSTRACT FROM AUTHOR]

Molybdenum carbide‐based carbon materials were investigated as a catalyst for hydrodeoxygenation (HDO) of guaiacol. Mechanochemical synthesis has been used as a novel approach to obtain a fine molybdenum carbide‐based carbon catalysts. Guaiacol was chosen as a bio‐oil model compound to estimate the potential of the catalysts. The catalytic tests were carried out at 4 MPa initial hydrogen pressure, 320 °C for 180 min in a batch autoclave reactor. Insert abstract text here. A feed mixture was 3.5 g guaiacol in 66.5 g hexadecane as a solvent. [ABSTRACT FROM AUTHOR]

The discovery of molecular ionic cocrystals (ICCs) of active pharmaceutical ingredients (APIs) widens the opportunities for optimizing the physicochemical properties of APIs whilst facilitating the delivery of multiple therapeutic agents. However, ICCs are often observed serendipitously in crystallization screens and the factors dictating their crystallization are poorly understood. We demonstrate here that mechanochemical ball milling is a versatile technique for the reproducible synthesis of ternary molecular ICCs in less than 30 min of grinding with or without solvent. Computational crystal structure prediction (CSP) calculations have been performed on ternary molecular ICCs for the first time and the observed crystal structures of all the ICCs were correctly predicted. Periodic dispersion‐corrected DFT calculations revealed that all the ICCs are thermodynamically stable (mean stabilization energy=−2 kJ mol−1) relative to the crystallization of a physical mixture of the binary salt and acid. The results suggest that a combined mechanosynthesis and CSP approach could be used to target the synthesis of higher‐order molecular ICCs with functional properties. [ABSTRACT FROM AUTHOR]

Ni nanopowder was synthesized from NiO through mechanically induced magnesiothermic NiO–Mg reaction that can also be regarded as a kind of progressive synthesis, or Mechanically induced Self-sustaining Reaction (MSR). The obtained powder was characterized by XRD, FESEM, and TEM. After 8 min of milling, the mixture ignited in the mill vial to yield Ni and MgO. The latter was removed by leaching with 18% HCl. The mean crystallite size of resultant Ni was found to have a value of 45–50 nm. [ABSTRACT FROM AUTHOR]

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The present work explores mechanosynthesis of lanthanum aluminate-based perovskite ceramics and corresponding effects on ionic-electronic transport properties. La 1- x Ca x AlO 3-δ (x = 0.05–0.20) nanopowders were prepared via one-step high-energy mechanochemical processing. Sintering at 1450 °C yielded dense ceramics with submicron grains. As-prepared powders and sintered ceramics were characterized by XRPD, XPS and SEM. Electrochemical studies showed that partial oxygen-ionic conductivity in prepared La 1- x Ca x AlO 3-δ increases with calcium content up to 10 at.% in the lanthanum sublattice and then levels off at ∼6 × 10−3 S/cm at 900 °C. La 1- x Ca x AlO 3-δ ceramics are mixed conductors under oxidizing conditions and ionic conductors with negligible contribution of electronic transport in reducing atmospheres. Oxygen-ionic contribution to the total conductivity is 20–68% at 900 °C in air and increases with Ca content, with temperature and with reducing p(O 2). Impedance spectroscopy results showed however that electrical properties of mechanosynthesized La 1- x Ca x AlO 3-δ ceramics below ∼800 °C are determined by prevailing grain boundary contribution to the total resistivity. [ABSTRACT FROM AUTHOR]

A novel, homogeneous, nanostructured and equiatomic (TiZrHfVNb)C 5 High Entropy Carbide (HEC) was successfully synthesised in a powder form by a mechanosynthesis process from the elemental mixture. This synthesis method for HECs, not previously reported, is simple, reproducible and carried out at room temperature. During milling, the transition metals (Ti, Zr, Hf, V and Nb) alloying and the diffusion of carbon (introduced as graphite) into the alloy structure are simultaneously induced, obtaining the expected (TiZrHfVNb)C 5 HEC. The room temperature method employed contrasts with those reported in the bibliography from binary carbides that are carried out at a very high temperature (1800–2200 °C), with the consequent energy savings. [ABSTRACT FROM AUTHOR]

Green mechanosynthesis, free solvent, has been used for preparing a series of supramolecular complexes. Through directional hydrogen bonds and π-cation interaction can be prepared complexes with different states of aggregation of matter, where stoichiometry plays an essential role. When the stoichiometric ratio between the two compounds was 1:1, a solid product is obtained. But, when the ratio is higher, products are obtained as gel or paste to reach low viscosity liquids. Also, the structure of such complexes that form three-dimensional aggregates between C 12 TAC and phenol derivatives can explain the different aggregation states for final products and this may be the key to understand the viscosity reduction mechanism. [ABSTRACT FROM AUTHOR]

Hydroxyfluorapatite Ca 10 (PO 4) 6 (OH)F (HFA) powders were prepared by mechanosynthesis method using planetary ball milling with various parameters. X-ray Diffraction (XRD), Infrared (IR) and Raman spectroscopies, Energy Dispersive X-ray (EDX) and Brunauer-Emmett-Teller (BET) methods were employed to characterize the synthesized nanoparticles. Four factors (rotation speeds of disk, mass of balls, initial mass of powder and milling time) were investigated to understand their effect on the milling process and the formation of HFA nanocrystallite. Taguchi's design, with just 16 experiments (an L16 orthogonal array), was used to evaluate the impact of these parameters on six distinct properties, namely the crystallite size (nm), the percentage of crystallinity, the specific surface area (m2/g), the Ca/P atomic ratio, the percentages of the apatite and calcite phases. The average effects of the milling parameters and the signal-to-noise ratio (SN) were discussed. ANOVA analysis was used to determine the importance, the proportion of factor participation and also the influence of process parameters on responses. The Taguchi results indicated that the mass of balls and the rotation speed were found to be the most influential factors on the purity of compounds. The ball to powder weight ratio (BPR) was also introduced to study its effect on the synthesis process. Transmission Electron Microscopy (TEM), Scanning Electronic Microscopy (SEM) and Dynamic Light Scattering (DLS) revealed that milled HFA powders contained a nano-sized agglomerate. Unlabelled Image • Taguchi methods was used for synthesis and characterization of hydroxyfluoroapatite. • Nanoparticles were characterized by XRD, IR, Raman, EDX, BET, SEM and TEM. • Impacts of grinding parameters on purity, composition and morphology were studied. • Balls'mass and disk rotation speed show the most effects on purity and Ca/P ratio. • Crystallite size and crystallinity are influenced by rotation speed and powder mass. [ABSTRACT FROM AUTHOR]

This contribution deals with the mechanochemical synthesis, characterization, and thermoelectric properties of tetrahedrite-based materials, Cu12-xMxSb4S13 (M = Fe2+, Zn2+, Cd2+; x = 0, 1.5, 2). High-energy mechanical milling allows obtaining pristine and substituted tetrahedrites, after short milling under ambient conditions, of stoichiometric mixtures of the corresponding commercially available binary sulfides, i.e., Cu2S, CuS, Sb2S3, and MS (M = Fe2+, Zn2+, Cd2+). All the target materials but those containing Cd were obtained as single-phase products; some admixture of a hydrated cadmium sulfate was also identified by XRD as a by-product when synthesizing Cu10Cd2Sb4S13. The as-obtained products were thermally stable when firing in argon up to a temperature of 350–400 °C. Overall, the substitution of Cu(II) by Fe(II), Zn(II), or Cd(II) reduces tetrahedrites’ thermal and electrical conductivities but increases the Seebeck coefficient. Unfortunately, the values of the thermoelectric figure of merit obtained in this study are in general lower than those found in the literature for similar samples obtained by other powder processing methods; slight compositional changes, undetected secondary phases, and/or deficient sintering might account for some of these discrepancies.

La2/3Cu3Ti4O12 (LCTO) powder has been synthesized by the mechanochemical milling technique. The pelletized powder was conventionally sintered for 10 h at a temperature range of 975–1025 °C, which is a lower temperature process compared to the standard solid-state reaction. X-ray diffraction analysis revealed a cubic phase for the current LCTO ceramics. The grain size of the sintered ceramics was found to increase from 1.5 ± 0.5 to 2.3 ± 0.5 μm with an increase in sintering temperature from 975 to 1025 °C. The impedance results show that the grain conductivity is more than three orders of magnitude larger than the grain boundary conductivity for LCTO ceramics. All the samples showed a giant dielectric constant (1.7 × 103–3.4 × 103) and dielectric loss (0.09–0.17) at 300 K and 10 kHz. The giant dielectric constant of the current samples was attributed to the effect of internal barrier layer capacitances due to their electrically inhomogeneous structure.

Abstract—X-ray diffraction, Mössbauer and Raman spectroscopy have been used to study structural phase transformations during mechanosynthesis of Fe–С60/70 in toluene with 20 and 25 at % С60/70 fullerite. The quantitative carbon content determines the phase composition of mechanocomposites. (Fe3C)D forms at 20 at % С60/70, whereas Fe7C3 and a paramagnetic phase form at 25 at % С60/70 at the initial stage of mechanical alloying. Free carbon is in an amorphous state in the sample. The formation mechanism of carbides and a paramagnetic component is discussed. [ABSTRACT FROM AUTHOR]

Solvent‐assisted ball milling is used to prepare the sulfide solid electrolyte Li7P3S11. Comparing with dry ball milling and simple liquid phase synthesis, solvent‐assisted ball milling can significantly promote the reaction of the starting materials from tens of hours to only several hours. When using dimethoxyethane as the assistant solvent, relatively pure Li7P3S11 with ionic conductivity of 1.0 × 10−4 S/cm can be synthesized after 8‐hour ball milling with following 2‐hour 180°C vacuum drying and 4‐hour 230°C heat treatment. It is revealed that the transition from the precursor to Li7P3S11 is a two‐step process, with an intermediate composed of a thio‐LISICON III analogous phase and an amorphous phase. This work not only provides a synthesis route of Li7P3S11 which reduces synthesis duration, but also offers an instructive insight into the phase evolution in solvent‐based synthesis process of sulfide solid electrolytes. [ABSTRACT FROM AUTHOR]

Solvent‐assisted ball milling is used to prepare the sulfide solid electrolyte Li7P3S11. Comparing with dry ball milling and simple liquid phase synthesis, solvent‐assisted ball milling can significantly promote the reaction of the starting materials from tens of hours to only several hours. When using dimethoxyethane as the assistant solvent, relatively pure Li7P3S11 with ionic conductivity of 1.0 × 10−4 S/cm can be synthesized after 8‐hour ball milling with following 2‐hour 180°C vacuum drying and 4‐hour 230°C heat treatment. It is revealed that the transition from the precursor to Li7P3S11 is a two‐step process, with an intermediate composed of a thio‐LISICON III analogous phase and an amorphous phase. This work not only provides a synthesis route of Li7P3S11 which reduces synthesis duration, but also offers an instructive insight into the phase evolution in solvent‐based synthesis process of sulfide solid electrolytes. [ABSTRACT FROM AUTHOR]

Highlights • Nanostructured materials obtained by Mechanosynthesis. • Milled co-product increase mechanical performances of substituted cement. • High-energy milling tends to produce more agglomerated particles. • The use of PCA reduce agglomeration phenomena. • Co-products mechanical activation improve pozzolanic reactions. Abstract In this study, we have modified slag and fly ashes by mechanosynthesis process carried out by high-energy ball milling using a planetary mill. In order to optimize the milling conditions, we have added process control agent (PCA). This PCA affects powders agglomeration phenomena during milling and impacts the milling time for the final product. We have studied the structure and microstructure of coproducts (fly ashes and slag) obtained by mechanical activation. In addition, we have also tested the mechanical performances of samples prepared with the addition of activated coproducts. [ABSTRACT FROM AUTHOR]

Abstract The nanoparticles of vanadium, niobium, and tantalum carbides were synthesized by a mechanically induced magnesiothermic combustion in the separate Mg/V 2 O 5 /C, Mg/Nb 2 O 5 /C, and Mg/Ta 2 O 5 /C systems. Initial materials in these systems ignited after short milling times of 10, 10, and 23 min, respectively. X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), energy-dispersive X-ray spectroscopy (EDS), high-resolution transmission electron microscopy (HRTEM) and elemental mapping techniques were employed to characterize the combustion products. In this process, magnesium reduces initial oxides to generate elemental V/Nb/Ta to react with carbon, forming the carbide phases. Highlights • Ultra-high temperature ceramics of VC, NbC, and TaC were mechano-synthesized through a magnesiothermic reduction. • High-energy ball milling was used to induce a combustion reaction inside the milling chamber. • The mechanism of the products formation was described. • The carbide compounds were characterized by various techniques. [ABSTRACT FROM AUTHOR]

Abstract The effect of polyvinyl alcohol, PVA, on crystallite and particle sizes of strontium hexaferrite synthesized by high-energy ball milling followed by an annealing at 950 °C is presented. Results of X-ray diffraction of (100-x)SrFe 12 O 19 @xPVA (0 ≤ x ≤ 100) composites shown the presence of strontium hexaferrite in all samples, while the crystal structure of PVA is degraded due to the mechanical energy supplied from the milling process. However, the Infrared study (FTIR) indicated that the polymeric chain kept intact. Magnetic behavior, from vibrating sample magnetometry tests, shown a waist wasp type hysteresis loop, for all the composites SrFe 12 O 19 @PVA, confirming that both materials do not generate bonds, and there is only a mixture of materials. Finally, Rietveld refinement, SEM analysis, and particle size measurement allowed demonstrating that PVA reduces the crystallite and particle sizes at nanometers scale of strontium hexaferrite synthesized. Highlights • SrFe 12 O 19 @PVA with different ratio were obtained by high energy ball milling using sapphire balls during 3 h. • The effect of mechanical mill in the PVA material is reported. • A magnetic model of SrFe 12 O 19 @PVA wasp waist is proposed. • Nanoparticles of strontium hexaferrite were obtained and liberated in water using PVA as encapsulator. • The best ratio is 25% of PVA and 75% of strontium hexaferrite. [ABSTRACT FROM AUTHOR]

Graphical abstract The solventless conversion of ZnO into CoZn-ZIF could be promoted by adding cobalt acetate as both Co source and catalyst. Physicochemically distinct CoZn-ZIFs could be obtained by introducing Co and Zn elements into the frameworks while keeping the overall framework intact, resulting in the enhancement of CO 2 uptake. Abstract An efficient and simple methodology was proposed to synthesize bimetallic Co–Zn based zeolitic imidazolate frameworks (CoZn-ZIFs; Co x Zn (1− x) (2-methylimidazole) 2) with sodalite topology. The synthesis strategy is based on a solventless mechanochemical reaction using only powder raw material, zinc oxide, cobalt acetate, and 2-methylimidazole, for ease of handling and large-scale production. The solventless conversion of ZnO into CoZn-ZIF could be promoted by adding cobalt acetate as both Co source and catalyst. A feature of the acetate-assisted mechanosynthesis is that CoZn-ZIF particles are tens of micrometers in size and hierarchically structured. Co and Zn elements are homogeneously dispersed in the framework. Tuning the additive amount of cobalt acetate could vary the Co/Zn ratio of CoZn-ZIF particles. Compared with Zn-ZIF prepared by adding zinc acetate, CoZn-ZIFs exhibited enhanced CO 2 uptake. The enhancement of 35% for CO 2 uptake capacity at 298 K and 100 kPa was displayed by Co 0.9 Zn 0.1 -ZIF as compared to Zn-ZIF. [ABSTRACT FROM AUTHOR]

Ball-milling technique as a solvent-free and an alternative green process was investigated for the eco-benign synthesis of bis(indolyl)-methanes (BIMs) from various aldehydes and selected ketones with indoles in high yields. The present methodology has several advantages such as simple procedure, good yields, mild conditions, and reduced environmental consequences. The silica gel acts both as a grinding medium and an acid catalyst. The utility of this technique was demonstrated by synthesizing library of 17 BIMs including two natural products trisindoline and tris(1H-indol-3-yl)methane. [ABSTRACT FROM AUTHOR]

Abstract Niobium carbonitride [Nb(C,N)] nanoparticles were synthesized by a combustive mechanochemical reaction in the Mg/Nb 2 O 5 /C 3 H 6 N 6 system. High-energy ball milling was used to promote a mechanically induced self-sustaining reaction (MSR). Combustion occurred after a very short milling period of 5 min. X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), energy-dispersive X-ray spectroscopy (EDS) and electron energy loss spectroscopy (EELS) analyses revealed that the nature of the product is an intermixed carbonitride material. The formation mechanism of Nb(C,N) resulted from the magnesiothermic reduction of niobium oxide to generate elemental Nb, which then reacted with the species generated from the melamine decomposition. Graphical abstract Elemental mappings showing the distribution of niobium, carbon, and nitrogen. fx1 [ABSTRACT FROM AUTHOR]

Abstract: The technology of formation of wear- and corrosion-resistant functionally gradient coatings by a method of microplasma sputtering of composite nanostructured powders was developed. The microhardness of obtained coatings reaches 10.27 GPa, providing effective protection of parts and components of precision engineering in extreme operating conditions. [ABSTRACT FROM AUTHOR]

• Four binary cocrystals have been synthesized utilizing liquid assisted grinding (LAG) method. • Conformationally flexible sulfur-containing bipyridines have been employed as molecular linkers with robust tripodal molecules as coformers to generate diverse network topologies. • SCXRD, PXRD, and thermal analyses were used to characterize all of the synthesized cocrystals. • The intermolecular interactions in each cocrystal were examined using a Hirshfeld surface analysis. Four binary cocrystals of cyanuric acid (CUA) and 5-aminoisophthalic acid (5AIPA) in combination with spacer aldrithiol-4 (ALDTHL) and 4,4′-dipyridyl sulfide (DPS) were prepared via Liquid Assisted grinding (LAG) method. Single crystal X-ray diffraction and powder X-ray diffraction techniques were used to elucidate their structures, which are further characterized using thermogravimetric analysis. While CUA produces 0.5:0.5 and 2:2 cocrystals with ALDTHL and DPS respectively; 5AIPA acid forms 1:1 cocrystals with both ALDTHL and DPS. Again, all the cocrystals adopt a sheet-like structure, with the exception of the (DPS) 2 •(CUA) 2 cocrystal, which displays an interpenetrated polycatenane type of molecular packing. In order to analyze the intermolecular interactions in the four cocrystals, Hirshfeld surface analysis was performed. [Display omitted] [ABSTRACT FROM AUTHOR]

The mechanism of strain localization of polycrystallic precipitation hardening materials based on the account of statistical dissipation in allocation of particles on slip planes and dissipation of the size of particles is proposed. The methods of computer simulation have shown that the decrease of the grain size of precipitation hardening alloy and the decrease of particles amount, contained in a grain and also the formation of particles polydisperse mixture at thecoagulative growth stage during aging, intensify the dissipation in allocation of particles on a matrix.

The results of investigation of structure evolution of powder composition of Fe/SiC during mechanical activation (MA) are described. It is shown that the mechono-composite Fe/SiC is formed by treatment of the composition of Fe/SiC powders in the mill with energy intensity of I = 3 W/g during a short time. The main stages of microstructure formation of the composite Fe/SiC powders include crushing, deformation mixing, submicrostructure fragmentation of components and forming of globular microstructure. The alignment of the phase composition and size range of the particles of mechano-composites Fe/SiC and SiC inclusions takes place during 60 minutes of the MA. The SiC particle size is decreased from 40–180 microns to 0,3–2 microns. The formation of the Fe/SiC composite by MA during 60 minutes occurs without significant interaction between the components.

Neodymium orthoferrite NdFeO3 was obtained at room temperature by mechanosynthesis with a stoichiometric ratio of Nd2O3 and Fe2O3 powders, whereas the traditional synthesis requires a temperature of approximately 1000 °C. The crystal structure was analyzed by X-ray diffraction analysis using Cu radiation and a LynxEye XE detector, whose strong fluorescence filtering enabled a high signal intensity. The analysis indicated that the obtained crystallites were nano-sized. The particle morphology was observed by scanning electron microscopy, and the magnetic saturation was tested by vibrating sample magnetometry. The synthesis of NdFeO3 was detected after a few hours of milling, indicating that the milling imparted mechanical energy to the system.