The one-pot method focuses on the reduction of the number of steps or chemical reactions in the synthesis of materials, and it is very appealing in terms of sustainability. In addition to this point of view, superconductors are desired materials due to their unusual properties, such as the zero resistivity and the perfect diamagnetism. One-pot, Thus, in this work, we described the one-pot synthesis of YBa2Cu3O7-δ superconducting ceramic. In just two steps and a few hours, a polymer composite solution was prepared, which originates a powder after burning the polymer out with pure phase and with superconducting properties better than those produced by other techniques.
Solid-state synthesis from powder precursors is the primary processing route to advanced multicomponent ceramic materials. Designing ceramic synthesis routes is usually a laborious, trial-and-error process, as heterogeneous mixtures of powder precursors often evolve through a complicated series of reaction intermediates. Here, we show that phase evolution from multiple precursors can be modeled as a sequence of pairwise interfacial reactions, with thermodynamic driving forces that can be efficiently calculated using ab initio methods. Using the synthesis of the classic high-temperature superco…
The powder of barium titanate (BaTiO3) synthesized by solid state was characterised by spherical grains of the average size about 500 nm. The double mechanical activation and calcination of raw materials was necessary to receive the monophase material. In order to improve the mouldability, the obtained barium titanate powder was granulated in spray drier. Pellets and beams from BaTiO3 granulate were manufactured by both uniaxial and isostatic pressing. The properties of barium titanate material at each stage of its fabrication (powder, granulate, sintered material) influencing on its applicati…
A two step solid state reaction route has been presented to synthesize monophasic cobalt tellurate (Co3TeO6, CTO) using Co3O4 and TeO2 as starting reagents. During synthesis, initial ingredient Co3O4 is found better than CoO in circumventing the intermediate Co5TeO8 or CoTeO3 phases. High resolution Synchrotron X-ray Diffraction has been used to probe different phases present in synthesized CTO and to achieve its single phase. Further, XANES studies near Co K and Te L-edge reveal mixed oxidation states of Co (i.e. Co2+ and Co3+) and +VI valence state of Te respectively, which is also confirmed…
Lead-free Ba0.85Ca0.15Zr0.10Ti0.90O3 (BCZT) ceramics have demonstrated excellent dielectric, ferroelectric and piezoelectric properties in comparison to lead-based materials. The synthesis of pure and crystalline BCZT nanopowders at low temperatures of 25, 80 and 160 C was reported previously by using a sol-gel method followed by a hydrothermal route. In this study, the structural, dielectric and ferroelectric properties of sintered BCZT ceramics at 1250 °C for 10h were investigated. XRD measurements revealed the presence of a single perovskite phase at room temperature with the coexistence of…
Macroscopic fibers of carbon nanotubes (CNT) have emerged as an ideal architecture to exploit the exceptional properties of CNT building blocks in applications ranging from energy storage to reinforcement in structural composites. Controlled synthesis and scalability are amongst the most pressing challenges to further materialize the potential of CNT fibers. This workshows that under floating catalyst chemical vapor conditions in the direct spinning method, used both in research and industry,the ceramic reactor tube plays an unsuspected active role in CNT growth, leading for example to doublin…
The site-doping strategy of barium titanate (BaTiO3) is a promising way to develop new lead-free materials for energy with enhanced dielectric and piezoelectric properties. A novel strategy to elaborated pure and crystalline Ba0.85Ca0.15Zr0.1Ti0.9O3(BCZT) ferroelectric powders at low temperature is proposed. It is based on sol-gel method followed by a hydrothermal reaction. The effects of preparation temperature on structure, crystallinity, purity, morphology and particles size distribution of BCZT powders were studied. It was clearly shown that pure and crystalline BCZT could be obtained over…
Ultra-high-temperature ceramics (UHTCs) are optimal structural materials for applications that require extreme temperature resilience, resistance to chemically aggressive environments, wear, and mechanical stress. Processing UHTCs with laser-based additive manufacturing (AM) has not been fully realized due to a variety of obstacles. In this work, selective laser reaction sintering (SLRS) techniques were investigated for the production of near net-shape UHTC ceramics such as HfC, ZrC, TiC, HfN, ZrN, and TiN. Group IV transition metal and metal oxide precursor materials were chemically converted…
Thermal expansion behavior at high temperatures of synthesized Na$_{1-x}$Zr$_2$(PO$_4$)$_{3-x}$(XO$_4$)$_x$, and Ca$_{1-x}$Zr$_2$(PO$_4$)$_{3-x}$(XO$_4$)$_x$, X = Mo, W compounds has been investigated. Ceramics with relatively high density (more than 97.5%) were produced by Spark Plasma Sintering (SPS) of submicron powders obtained by sol-gel synthesis. The study of strength characteristics has revealed that hardness the ceramics are greater than 5 GPa, and minimum fracture toughness factor was 1 MPa*m$^{1/2}$. It was found that ceramics have a high hydrolytic resistance in the static regime -…
The transparent Er, Nd co-doped Yttria ceramics with transparency around 78 percentage (in 500 - 2000 nm range without Fresnels correction) were fabricated successfully. It involved nanoparticle synthesis by coprecipitation method and sintering of pellets under high vacuum condition. The crystalline phase, particle size and element composition were confirmed by X- ray diffraction, scanning electron microscope, energy dispersive X- ray fluorescence techniques, respectively. The upconversion luminescence mechanisms involving energy transfer and non-radiative relaxation were analyzed. It is expec…
Titanium diboride (TiB2) is a low-density refractory material belonging to the family of ultra-high temperature ceramics (UHTCs). This paper reports on the production and microstructural and optical characterization of nearly fully dense TiB2, with particular interest to its potential utilization as novel thermal solar absorber. Monolithic bulk samples are produced starting from elemental reactants by a two-step method consisting of the Self-propagating High-temperature Synthesis (SHS) followed by the Spark Plasma Sintering (SPS) of the resulting powders. The surface of obtained samples has-be…
The bulk samples of CuO and Fe-doped CuO were synthesized by ceramics methods. Structural and compositional analyses were performed by using X-ray diffraction, SEM, and EDAX. Through this manuscript, we are going to report the effect of trivalent iron doping (Fe$^{3+}$) in copper (II) oxide (Cu$_{0.95}$Fe$_{0.05}$O) bulk samples on magnetic and dielectric behavior. The paramagnetic phase has been established in CuO as a result of Fe$^{3+}$ doping. The strong correlation between magnetic and dielectric properties indicated spin-polaron interaction at the transition temperature. Bulk CuO and als…
The development of damage-resistant structural materials that can withstand harsh environments is a major issue in materials science and engineering. Bioinspired brick-and-mortar designs have recently demonstrated a range of interesting mechanical properties in proof-of-concept studies. However, reproducibility and scalability issues associated with the actual processing routes have impeded further developments and industrialization of such materials. Here we demonstrate a simple approach based on uniaxial pressing and field assisted sintering of commercially available raw materials to process…
Structural and Optical properties of the (Na0.5 K0.5)y Li 1-y NbO3 (y = 0.934 & 0.936) ceramics have been explored in terms of the X-Ray diffraction patters, Rietveld analysis, UV-Vis spectroscopy, and Kubelka-Munk functions. Rietveld analysis of both these structures reveals them to be tetragonal with space group P4mm. It is found that increase in Li doping increases the optical band gap. Presence of additional hardening dopant MnO2 is found to have a uniform behavior for both these composition. With increasing MnO2 concentration, the band gap decreases indicative of increase in B-site cation…
Copper oxide II is a p-type semiconductor that can be used in several applications. Focusing on producing such material using an easy and low-cost technique, we followed an acetate one-pot-like route for producing a polymer precursor solution with different acetates:PVP (polyvinylpyrrolidone) weight ratios. Then, composite nanofibers were produced using the solution blow spinning (SBS) technique. The ceramic CuO samples were obtained after a calcination process at 600 oC for two hours, applying a heating rate of 0.5 oC/min. Non-woven fabric-like ceramic samples with average diameters lower tha…
Aviation's fossil fuel emissions contribute to global warming. The production and disposal of the materials used in aircrafts too. The current metallic alloys present in the hot section of engines pose constraints in terms of temperature, pressure and weight that restrain the performance of the aircrafts. Also, these alloys are produced using rare, depleting resources, and polluting processes. In this paper, we hypothesize the use of bioinspired nacre-like alumina (NLA), a ceramic material that exhibits unusual toughness, and evaluate its potential as a replacement for superalloys in aircraft'…
The use of microwave irradiation is a promising alternative heat source for the synthesis of inorganic materials such as perovskite oxides. The method offers massive energy and time savings as compared to the traditional ceramic method. In this work we review the basic principles of the microwave heating mechanism based on interactions between dipoles in the material and the electromagnetic microwave. Furthermore, we comment on and classify all different sub-types of microwave synthesis such as solid-state microwave and microwave assisted hydrothermal synthesis. In the experimental part of thi…
We describe the first-principles design and subsequent synthesis of a new material with the specific functionalities required for a solid-state-based search for the permanent electric dipole moment of the electron. We show computationally that perovskite-structure europium barium titanate should exhibit the required large and pressure-dependent ferroelectric polarization, local magnetic moments, and absence of magnetic ordering even at liquid helium temperature. Subsequent synthesis and characterization of Eu$_{0.5}$Ba$_{0.5}$TiO$_3$ ceramics confirm the predicted desirable properties.
Heterogeneous sonochemical method was applied for synthesis of novel superconducting nanocomposites consisting of magnetic (and/or nonmagnetic) nanoparticles embedded into the bulk of ceramic superconductors. In addition to in-situ production of the efficient pinning centers, this synthesis method considerably improves the interbrain coupling. Significant enhancement of the magnetic irreversibility is reported for Fe2O3 nanoparticles embedded into the bulk of MgB2 superconductor. Nonmagnetic Mo2O5 nanoparticles also increase pinning strength, but less than magnetic Fe2O3. Detailed magnetizatio…
Ultra-high-temperature ceramics (UHTCs) are candidate structural materials for applications that require resiliency to extreme temperature (>2000°C), high mechanical loads, or aggressive oxidizing environments. Processing UHTC transition metal carbides as standalone materials using additive manufacturing (AM) methods has not been fully realized due to their extremely slow atomic diffusivities that impede sintering and large volume changes during indirect AM that can induce defect structures. In this work, a two-step, reactive AM approach was studied for the formation of the ultra-high temperat…
A promising method for obtaining ceramic components with additive manufacturing (AM) is to use a two-step process of first printing the artifact in polymer and then converting it to ceramic using pyrolysis to form polymer derived ceramics (PDCs). AM of ceramic components using PDCs has been demonstrated with a number of high-cost techniques, but data is lacking for fused filament fabrication (FFF)-based 3-D printing. This study investigates the potential to use the lower-cost, more widespread and accessible FFF-based 3-D printing of PDCs. Low-cost FFF machines have a resolution limit set by th…
Modeling phase separation in polymer-derived silicon carbonitride ceramics through extended machine learning molecular dynamics
Université de Strasbourg（斯特拉斯堡大学）；Laboratoire ICube UMR 7357（ICube 实验室）；ADYNMAT CNRS consortium（ADYNMAT CNRS 联盟）；Institut de Physique et Chimie des Matériaux de Strasbourg, UMR 7504（斯特拉斯堡材料物理与化学研究所）；Centre for Catalysis and Clean Energy, School of Environment and Science, Griffith University（格里菲斯大学环境与科学学院催化与清洁能源中心）
Synthesis and Characterization of Compositionally Complex (Gd/Ho/Er/Dy)2Zr2O7 Thin Film Combinatorial Library
The University of Tennessee, Knoxville（田纳西大学诺克斯维尔分校）；Laser Thermal（激光热技术公司）；The University of Virginia（弗吉尼亚大学）；Center for Nanophase Materials, Oak Ridge National Laboratory（橡树岭国家实验室纳米材料中心）；National Synchrotron Light Source II, Brookhaven National Laboratory（布鲁克海文国家实验室第二代同步辐射光源）；National Institute of Standards and Technology（美国国家标准与技术研究院）
Samarium doped BiFeO3 compounds having nano-size crystallites were prepared by the ethylene glycol assisted sol-gel synthesis method. X-ray diffraction and SEM measurements as well as Raman spectroscopy and FTIR experiments were used to clarify the evolution of the crystal structure on microscopic and local scale levels in the compounds having formula Bi1-xSmxFeO3, where x equals from 0 to 1. Magnetization measurements along with the structural data were used to determine a correlation between magnetic properties and crystal structure of the compounds. The compounds with from x 0.1-0.2 are cha…
A complex oxalate precursor, CaCu3(TiO)4(C2O4)8.9H2O, was synthesized and the precipitate that obtained was confirmed to be monophasic by the wet chemical analyses, X-ray diffraction, FTIR absorption and TG, DTA analyses. The thermal decomposition of this oxalate precursor led to the formation of phase-pure calcium copper titanate, CaCu3Ti4O12, at 680oC. The bright field TEM micrographs revealed that the size of the as synthesized crystallites to be in the 30 to 80 nm range. The powders so obtained had excellent sinterability resulting in high density ceramics which exhibited giant dielectric …
The present work describes a synthesis route for bulk Ta4AlC3 MAX phase ceramics with high phase purity. Pressure assisted densification was achieved by both hot pressing and spark plasma sintering of tantalum hydride, aluminium and carbon powder mixtures in the 1200-1650°C range. The phases present and microstructures were characterized as a function of the sintering temperature by X-ray diffraction and scanning electron microscopy. High-purity alfa-Ta4AlC3 was obtained by hot pressing at 1500°C for 30 min at 30 MPa. The beta-Ta4AlC3 allotrope was observed in the samples produced by SPS. The …
The electrocaloric (EC) effect and energy storage properties of eco-friendly ferroelectric Ba0.9Sr0.1Ti1-xSnxO3 (BSTS-x) ceramics prepared by the conventional solid-state reaction method were studied. Significant energy efficiency exceeding 80% was found in our samples. In particular, BSTS-5 and BSTS-10 samples exhibit 92% and 88% efficiency, respectively, over a wide temperature range around room temperature (RT). Direct EC measurement and an indirect method based on the thermodynamic approach were used to characterize the EC effect, and both yielded consistent results. The largest electrocal…
Temperature-dependent dielectric permittivity of lead-free (LixNa1-x)NbO3 for nominal x = 0.04-0.20, prepared by solid state reaction followed by sintering, was studied to resolve often debated issue pertaining to exactness of morphotropic phase boundary (MPB) location along with structural aspects and phase stability in the system near MPB. Interestingly, a diffuse phase transition has been observed in the dielectric permittivity peak arising from the disorder induced in A-site and structural frustration in the perovskite cell due to Li substitution. A partial phase diagram has been proposed …
The present work reports synthesis, as well as a detailed and careful characterization of structural, magnetic, and dielectric properties of differently tempered undoped and doped CaCu3Ti4O12 (CCTO) ceramics. For this purpose, neutron and x-ray powder diffraction, SQUID measurements, and dielectric spectroscopy have been performed. Mn-, Fe-, and Ni-doped CCTO ceramics were investigated in great detail to document the influence of low-level doping with 3d metals on the antiferromagnetic structure and dielectric properties. In the light of possible magnetoelectric coupling in these doped ceramic…
Multiferroic materials attract considerable interest because of the wide range of potential applications such as spintronic devices, data storage and sensors. As a strong candidate for the applications among the limited list of single-phase multiferroic materials, BiFeO3 (BFO) is a quite attractive material due to its multiferroic properties at room temperature (RT). However, BFO is widely known to have large leakage current and small spontaneous polarization due to the existence of crystalline defects such as oxygen vacancies. Furthermore, the magnetic moment of pure BFO is very weak owing to…
As candidate tritium breeder materials for use in the ITER helium cooled pebble bed, ceramic multiphasic compounds lying in the region of the quasi-binary lithium metatitanate- lithium orthosilicate system may exhibit mechanical and physical advantages relative to single phase materials. Here we present an organometallic solution-based synthesis procedure for the low-temperature fabrication of compounds in the Li2TiO3 - Li4SiO4 region and investigate phase stability and transformations through temperature varied X-ray diffraction and scanning calorimetry. Results demonstrate that the metatitan…
We have been able to synthesize Lu+3 substituted La0.67Ca0.33MnO3 (LCMO) by an auto-combustion method. Synthesis of this compound is not successful by conventional ceramic or other chemical methods. Magnetic and electrical transport properties of the Lu substituted LCMO [(La1-xLux)0.67Ca0.33MnO3 (0 < x < 0.12)] system have been investigated and compared with those of the Y+3, Pr+3, Dy+3 and Tb+3 substituted LCMO systems. All the compounds show a ferromagnetic metal to paramagnetic insulator transition at TC. The tolerance factor reduces from 0.917 for x = 0 to 0.909 for x = 0.12 and for this r…
The (Co,Ni)Al2O4 is an aluminum transition metals oxide which falls into the category of aluminate spinels. The synthesis of nano-crystalline spinels has been investigated extensively due to their potential applications such as a high-density magnetic recording, microwave devices magnetic fluids, ceramic pigment as well as a heterogeneous catalytic material. In the present study, attempts have been made to synthesise the nano-crystalline (Co,Ni)Al2O4 spinel powders by ball milling and subsequent annealing. An alloy of Al70 Ni15 Co15, exhibiting the formation of a complex intermetallic compound…
Preparation and magnetic properties of (Ln0.2La0.2Nd0.2Sm0.2 Eu0.2)MnO3 (Ln = Dy, Ho, Er) high-entropy perovskite ceramics containing heavy rare earth elements
Study on mechanical properties of one-dimensional layered titanate nanomaterials is crucial since they demonstrate important applications in various fields. Here, we conducted ex situ and in situ atomic-scale investigation on bending properties of a kind of ceramic layered titanate (Na2Ti2O4(OH)2) nanowires in a transmission electron microscopy. The nanowires showed flexibility along <100> direction and could obtain a maximum bending strain of nearly 37%. By analysing the defect behaviours, the unique bending properties of this ceramic material was found to correlate with a novel arrangement o…
Synthesis methodology for flakes of p-terphenyl through sublimation under inert atmosphere of argon is presented. Flake morphology of p-terphenyl provides a favourable environment for efficient intercalation of potassium. Ratio of potassium and p-terphenyl is adjusted so as to obtain the desired superconducting phase i.e. potassium doped p-terphenyl (K3C18H14). A clear transition is observed at 107 K under Zero Field Cooled (ZFC) and Field Cooled (FC) mode. But overall the moment is positive possibly due to impurity phase dominating characteristics in the presence of negligible superconducting…
The full-potential linearized augmented plane wave method with the generalized gradient approximation for the exchange-correlation potential (FLAPW-GGA) is used to predict the electronic and elastic properties of the newly discovered superconducting nanolaminate Ti2InC. The band structure, density of states and Fermi surface features are discussed. The optimized lattice parameters, independent elastic constants, bulk and shear moduli, compressibility are evaluated and discussed. The elastic parameters of the polycrystalline Ti2InC ceramics are estimated numerically for the first time.
An efficient protocol for the synthesis of differently substituted 1, 4-dihydropyridines in deep eutectic solvents under solvent-free conditions is reported herewith. Excellent yields of the resultant products have been obtained. Recyclability studies have also been performed for deep eutectic solvents with very little loss in activity up to five recycles.
The powdery nature and high alkali content of vegetable ashes make them ideal raw materials to be used as modifiers of silicate compositions (glasses, enamels and ceramics). Their utilisation since ancient times is described in the literature of the history of glasses, but studies on the analyses of their composition are still limited. We discuss here the compositions of tree and shrub ashes (wattle, hawthorn, oak, green oak, olive wood, elm, poplar, apple tree, vine shoot), of plants (carex, fern, dogwood), of cereals (wheat, maize, rice), threshing waste and hay, mainly harvested in Maconnai…
The present paper describes in situ preparation of Ni° nanoparticles immobilized on acid activated montmorillonite K10 (Ni°-Mont) by impregnation of Ni(OAc)2 into nanopores of acid activated montmorillonite K10 followed by polyol reduction. Ni° NPs was highly dispersed into the initiated mesopores on the surface or inside swelled-interlayers of the examined clay with average size of 10-20 nm. Acid treatment of montmorillonite was carried out with HCl (4 M) under controlled conditions for generation of the desired pore sizes as a host of Ni° NPs. The prepared Ni°-Mont was used as a highly effic…
A facile one-pot hydrothermal synthesis as an efficient method to modulate the potassium content of cryptomelane and its effects on the redox and catalytic properties
We report the synthesis and theoretical investigations of three novel pseudo-peptide molecules derived from 2-amino-2-(1H-indole-2-yl) acetamides. The compounds were subjected to spectroscopic characterization ($^1$H, $^{13}$C-NMR and MS) and their chemical, electronic, and optical properties have been investigated. To ascertain their potential pharmacological applicability, the prospective reactive centers and molecular sites prone to interaction with water were identified along with possible sensitivity to autoxidation. Further, we have studied the optical response in the presence of differe…
