Solid-state Mechanism Research Articles

A novel technique for the synthesis of Au3N and its characterization using X-ray diffraction and Raman scattering techniques

We report a novel technique for the synthesis of Au3N via a solid-state diffusion-reaction mechanism. X-ray diffraction indexing confirmed that the structure of Au3N is anti-ReO3 with a lattice constant aAuN̄ of 4.065 ± 0.004 Å. The low value of lattice constant as compared to that of pristine gold, aAū of 4.080 ± 0.004 Å, is because of the LN2 quenching-induced structural squeezing. The structural squeezing caused compressive strain, leading to a compressed and rigid structure of Au3N. This is also supported by the shifting of characteristics, where the Raman peak shifted to the higher frequency side with an increased value of the full width at half maxima. The Raman shift of Au3N was found to be 1127.5 ± 0.3 cm−1, which is in good agreement with the theoretically calculated value obtained using density-functional theory. The prospects and future directions for the development of this novel gold nitride material are discussed.

Accelerated Solid-State Electrolyte Synthesis via Reaction Equilibria Manipulation

Solid-state electrolytes enable the use of a lithium metal anode and offer higher energy density and thermal stability, making all-solid-state batteries (ASSBs) a promising next-generation battery technology. Solid-state synthesis is the main method of synthesizing solid-state electrolytes, such as ceramic garnet-type oxide electrolytes. Solid-state reactions can be challenging due to typically requiring a long time at very high temperatures to allow ion migration and overcome the high activation energy of the forward reaction, making scale-up impractical. Our research focuses on understanding the solid-state reaction mechanisms using a model material, Li6.5La3Zr1.5Ta0.5O12 (LLZTO), renowned for its high lithium-ion conductivity and compatibility with lithium metal anodes. We propose a strategy to manipulate the solid-state reaction equilibrium to expedite LLZTO formation to less than one hour. Operando X-ray diffraction (XRD) and ex-situ XRD were used to study the reaction progress and evolution formation mechanisms. Characterization of composition and electrochemical properties is conducted using inductively coupled plasma optical emission spectroscopy (ICP-OES) and various electrochemical analytical techniques. This presentation aims to elucidate the feasibility of synthesizing LLZTO materials within a shorter timeframe, offering valuable insights for expediting the synthesis of solid-state electrolytes through solid-state reactions.

Solid-State Phase Transformation Kinetics and Mechanisms in Additively Manufactured Ti–6Al–4V Studied Using In-Situ High-Energy Synchrotron X-ray Diffraction

Solid-State Phase Transformation Kinetics and Mechanisms in Additively Manufactured Ti–6Al–4V Studied Using In-Situ High-Energy Synchrotron X-ray Diffraction

Infrared spectra of solid-state ethanolamine: Laboratory data in support of JWST observations

Context. Ethanolamine (NH2CH2CH2OH; EA) has been identified in the gas phase of the interstellar medium within molecular clouds. Although EA has not been directly observed in the molecular ice phase, a solid-state formation mechanism has been proposed. However, the current literature lacks an estimation of the infrared band strengths of EA ices, which are crucial data for quantifying potential astronomical observations and laboratory findings related to their formation or destruction via energetic processing. Aims. We conducted an experimental investigation of solid EA ice at low temperatures to ascertain its infrared band strengths, phase transition temperature, and multilayer binding energy. Since the refractive index and the density of EA ice are unknown, the commonly used laser interferometry method was not applied. Infrared band strengths were determined using three distinct methods. In addition to evaluating EA band strengths, we also tested the advantages and disadvantages of different approaches used for this purpose. The obtained lab spectrum of EA was compared with the publicly available MIRI MRS James Webb Space Telescope observations towards a low-mass protostar. Methods. We used a combination of Fourier-transform transmission infrared spectroscopy and quadrupole mass spectrometry. Results. The phase transition temperature for EA ice falls within the range of 175 to 185 K. Among the discussed methods, the simple pressure gauge method provides a reasonable estimate of band strength. We derived a band strength value of about 1 × 10−17 cm molecule−1 for the NH2 bending mode in the EA molecules. Additionally, temperature-programmed desorption analysis yielded a multilayer desorption energy of 0.61±0.01 eV. By comparing the laboratory data documented in this study with the JWST spectrum of the low-mass protostar IRAS 2A, an upper-limit for the EA ice abundances was derived. Conclusions. This study addresses the lack of quantitative infrared measurements of EA at low temperatures, crucial for understanding EA’s astronomical and laboratory presence and formation routes. Our approach presents a simple yet effective method for determining the infrared band strengths of molecules with a reasonable level of accuracy.

High-voltage and highly reversible redox chemistry of in situ cross-linked polydiphenylamine as an aqueous zinc battery cathode

Organic redox-active materials are promising electrode candidates for the next generation of rechargeable batteries owing to their versatile redox chemistry, sustainability, and potential low cost. Here, we present polydiphenylamine as a moderately high-voltage (1.25 V vs. Zn) and highly reversible organic cathode for aqueous zinc batteries. As revealed by cyclic voltammetry and spectroscopic analysis, the chemical oxidation–derived diphenylamine dimer electrochemically transforms into a cross-linked polymeric material during the first electrochemical oxidation (charge), which then operates by p-doping/dedoping redox of the amine center and a pseudocapacitor-like solid-state charge storage mechanism during the subsequent discharge-charge cycles. With an 80 wt% active loading, the polymer cathode delivers a specific capacity of 138 mAh/g at 100 mA/g, with 73% retention over 1000 cycles at a 99.8% Coulombic efficiency. Excellent rate capability is evidenced by 87 mAh/g capacity at 400 mA/g and highly stable cycling of over 1200 cycles under variable current rates. Facile one-step synthesis, fast charge storage kinetics, and attractive electrochemical performance establish polydiphenylamine as a notable organic cathode candidate for aqueous zinc batteries.

Kinetics study of pyrolysis of petroleum sludge and characterization of char

Thermochemical conversion (or pyrolysis) has emerged as an effective technique for the disposal of sludge generated in process industries. This paper reports physicochemical characterization and kinetic analysis of pyrolysis of sludge from a petroleum refinery and characterization of resultant char. The sludge had high volatile matter (>70 wt%) and low ash content (15 wt%). Pyrolysis of sludge was studied using a thermo-gravimetric analyzer (TGA). The TGA data was analyzed using two isoconversional models, viz. KAS and Vyazovkin AIC are used for the deduction of kinetic triplets, viz. activation energy, pre-exponential factor, and reaction mechanism. The activation energy (Ea ) of sludge pyrolysis varied in the 64.79–190.37 kJ/mol range. The pre-exponential factor varied from 1.18E + 07 to 4.29E + 12 s−1. The predominant solid-state mechanism of thermal conversion was an order-based reaction (F2/F3). The thermodynamic factors (viz. ΔH, ΔS, ΔG) of sludge pyrolysis were also determined. Relatively small values of (Ea – ΔH) ∼ 5 kJ/mol revealed high susceptibility of sludge for thermal conversion. Residual char after pyrolysis was characterized for physicochemical properties. The char properties were fixed carbon = 54.37%, calorific value = 22.48 MJ/kg, and BET surface area = 18.35 m2/g. These properties make char suitable for numerous applications.

A comprehensive exploration of pure and Zn doped LaFeO3 nanoparticles synthesized by solid state mechanism for charge storage devices

A comprehensive exploration of pure and Zn doped LaFeO3 nanoparticles synthesized by solid state mechanism for charge storage devices

Tunable multi-peak emission solid-state fluorescent carbon dots: Luminescence regulation mechanism and application in single-component-based LEDs

The design of solid-state fluorescent carbon dots (CDs) with multi-peak emission has become an urgent challenge to be solved with the in-depth research of CDs in LEDs. Here, one- and two-component solid-state white light CDs are synthesized by microwave-assisted hydrothermal method using the biological pollutant cyanobacteria, respectively. The solid-state fluorescence quantum yield of the one-component CDs was as high as 41.8 %, and the solid-state fluorescence mechanism of CDs is discussed to be mainly attributed to the self-quenching-resistant feature of “core-shell” structure and the reabsorption/RET-induced long-wavelength red light emission, and attenuation of the short emission wavelength. For two-component white light CDs, blue- and red-light CDs are obtained by simple dialysis separation, realizing the fluorescence tunability. The different origins of their multi-peak emission are discussed: core, edge and surface states. The synthesis yields of CDs are up to 62 %, enabling stable gram-scale production. The white- and red-light CDs are used as phosphors to fabricate fluorescent films and cold, pure, and warm white- and red-light LEDs with good resistance to photobleaching and temperature stability and CRI of 84.4, 85.7 and 61.5.

Electronic Properties of [Ru(NH3)6][M(CN)6] Double-Complex Crystals and Their Thermal Decomposition to Prussian Blue Analogs

The complex ions, [Ru(NH3)6]2+/3+ and [Fe(CN)6]3-/4-, are well known redox couples exhibiting fast interfacial and homogeneous electron transfer rates in aqueous solution. Here we show that when mixed together, they form insoluble double-complex Ax[Ru(NH3)6][Fe(CN)6] crystals with rhombohedral symmetry, where A is a cationic species and 0≤x≤2. The analogous interactions of [Ru(NH3)6]2+/3+ with [Ru(CN)6]3-/4- produces Ax[Ru(NH3)6][Fe(CN)6] crystals. Electrical measurements of these single crystals exhibit ohmic current-voltage responses, with corresponding conductivities on the order of 0.1 mS/m. We propose a solid-state charge transport mechanism based on Marcus theory for homogeneous outer-sphere electron transfer.Thermal decomposition at mild temperatures removes ammine ligands and transforms these crystals into nanopolycrystalline Prussian blue analogs (PBAs) that retain the macroscopic geometry of the double-complex crystals but adopt the familiar highly defected porous crystal structure and intervalence charge transfer characteristics of PBAs.

Real-time emissivity measurements on solid phase formation and its degree of structural disorder during solidification of SrAl2Si2O8 from molten state

An in-situ real-time study on solid phase formation and its degree of structural disorder could shed light on the mechanisms of solidification from the liquid and allow insight into the creation of materials designed to possess enhanced properties and facilitate their production and application. The implementation of a Rapid Scan technique on a FT-IR emissometer designed to allow the observation of materials under extreme temperature conditions allows following the liquid to solid-state phase transition mechanisms through time-resolved emissivity spectra acquired at a speed of 20 spectra per second. The cooling rate of the material can be modified by controlling the laser-heating system. This technique has been validated on SrAl2Si2O8 feldspar, a material which displays structural disorder. The technique is sufficiently accurate to determine small changes in the linewidths of spectra obtained at different cooling rates, suggesting that structural order is increased at slower cooling speeds and confirming the Al/Si ordering dependence on thermal history.

The influence of hydrogen on the synthesis of biocompatible alloy Ti-6Al-7 Nb by a new Hydride Cycle method

The Hydride Cycle (HC) method is proposed as a new approach for synthesis of biocompatible alloy Ti-6Al-7 Nb. In this approach, preliminary, (Ti-7 Nb)H3.81 hydride is synthesised by Self-propagating High-temperature Synthesis (SHS) method. The heating of a mixture of this hydride with aluminum, (Ti-7 Nb)H3.81+6Al, at 1000°C for 30 minutes in the HC device results in the synthesis of Ti-6Al-7 Nb alloy containing the α- and β-phases of Ti, 92 wt% and 8 wt%, respectively. The alloy interacted with hydrogen in the combustion mode (SHS) forming the hydride (Ti-6Al-7 Nb)H3.17 with hydrogen content 3.07 wt%. This amount of hydrogen ensures the brittleness of the hydride and its grinding for 30–40 minutes to the agglomerates down to submicron or nano sizes. The presence of hydrogen in the crystal lattice enhances the plasticity of the hydride facilitating its compaction. The compaction of the (Ti-6Al-7 Nb)H3.17 alloy hydride and dehydrogenation under T=1000°C results in the reaction-activated sintering and the formation of practically porous less Ti-6Al-7 Nb alloy. The HC synthesis of the biocompatible alloy Ti-6Al-7 Nb compiled with SHS mode of the hydride synthesis is provided with the several advantages over the traditional methods. It is a low temperature, short duration, waste less process, proceeding by solid-state mechanism without melting of components, being an energy-saving in total. The proposed HC approach for synthesis of Ti-6Al-7 Nb alloy in combination with the high-technology SHS process for the hydrides formation can be used in manufacturing the biocompatible alloys. The hydrogenation-sintering of the alloy hydride (Ti-6Al-7 Nb)H3.17 can be used for producing of items of any designed complex form, particularly of implants.

Numerical Simulation and Modeling of Mechano–Electro–Thermal Behavior of Electrical Contact Using COMSOL Multiphysics

Electrical contacts are important circuit components with diverse industrial applications, and their failure can lead to multiple unwanted effects. Hence, the behavior of electrical contacts is a widely studied topic in the scientific literature based on various approaches, tools, and techniques. The present study proposes a new approach to numerical modeling and simulation based on the Holm contact theory, aiming to study the dependence between the electric potential and the temperature within an electrical contact. Structured in five sections, the research was conducted using COMSOL Multiphysics software and its solid-state mechanics, electric current, and heat transfer modules in order to highlight contact behavior from mechanical, electrical and thermal points of view: the von Mises stress, contact force, electric field amplitude, variation of the electrical potential along the current path, temperature gradient, and dependence of temperature along the contact elements edges were obtained by simulation, and are graphically represented. The results show that the temperature increase follows a parabolic curve, and that for values higher than 4 mV of voltage drop, the temperature of the contact increases to 79.25 degrees (and up to 123.81 degrees for 5 mV) over the ambient temperature, thus the integrity of insulation can be compromised. These values are close (10–12%) to the analytically calculated ones, and also in line with research assessed in the literature review.

Atomic insights into the solid-state amorphization mechanism of amorphous/crystalline dual-phase Mg alloys

The amorphous/crystalline (A/C) dual-phase structure is a new design strategy to improve the comprehensive performance of Mg alloys. However, the regulation mechanism of the amorphous phase size of the dual-phase Mg alloys is still unclear. Here, the mechanism and size effect of solid-state amorphization of the dual-phase Mg alloys is investigated using molecular dynamics/Monte Carlo simulations. The results indicate that the degree of solid-state amorphization of the dual-phase Mg alloys depends on three factors: the original size of amorphous phase, the diffusion of rare earth element Y, and A/C interface (ACI). The degree of solid-state amorphization of the alloys exhibits a significant size effect on the original size of amorphous phase. Except for the two models with the smaller original size of the amorphous phase, the degree of solid-state amorphization of the alloys decreases significantly with the increase of the original size of amorphous phase. It is worth noting that after relaxation, as the original size of amorphous phase increases, the distribution of Y atoms in the amorphous phase undergoes a transition from uniform distribution to segregation, and the larger the original size of amorphous phase, the more obvious the segregation phenomenon becomes. The results indicate that the segregation of Y atoms in the amorphous phase suppresses the solid-state amorphization of the alloys. The results show that the segregation of Y atoms in the alloys requires a larger original size of the amorphous phase and the presence of ACI, both of which are essential.

Correct Use of Oscillating-Cup Viscometers for High-Temperature Absolute Measurements of Newtonian Melts

Oscillating-body viscometers have been used in the past to measure, in an absolute way, the viscosity of molten materials at high temperatures, from salts, metals, alloys, and semiconductors. However, the simultaneous use of basic or incomplete mathematical models, to mimic the experiment, and less careful engineering solutions for the design and operation of the instruments, led in the past to high discrepancies between the data obtained in several laboratories. This was caused by the incorrect use of the method’s theory, less accurate solutions of the complex solutions, that involve solid state and fluid mechanics, and unreal instrument design. From these types of viscometers, oscillating-cup instruments have had the most success in measuring viscosity at high temperatures, and they will be the object of this paper. It was written as a resource for workers interested in transport properties of materials when considering its use for the absolute measurement of fluids viscosity in their work, or in judging the results of others' work when comparing data with their own. The paper starts with the most accurate theory of the method’s description, followed by a discussion of its validity, application to instrument design, and consequent operation. Several constraints were identified and recommendations were made to minimize the effects of failing to satisfy them. Finally, a discussion about the uncertainty budget calculations for a real experiment is made. If all these points are followed in the design and operation of the instrument, results in global uncertainties Ur(η) between 0.02 and 0.04 are possible to obtain, up to high temperatures. If these constraints are not satisfied, erroneous measurements can be made, making comparisons and quality assessment difficult.

Internal and external variables influencing microwave dielectric properties of (1-x)Mg(Zr0.05Ti0.95)O3-xSrTiO3 ceramics

The physical and chemical state of ceramics are very important for their microwave dielectric properties, especially at high frequencies above GHz. Therefore, the microstructure and microwave dielectric properties of (1-x)Mg(Zr0.05Ti0.95)O3–xSrTiO3((1-x)MZT–xST) ceramics were investigated by controlling external variables. The compounds were synthesized through a solid-state reaction mechanism and sintered at relatively low temperatures. A cavity resonator method was employed to analyze the microwave dielectric properties. Optimal sintering conditions significantly enhanced the microwave dielectric performance of MZTST ceramics. The addition of ZnO substantially reduced the sintering temperature and equilibrium sintering time, enabling the activation of optimal conditions and the achievement of temperature-stable microwave dielectrics like NP0: εr ∼20.16 at 10 GHz, Qf of ∼81839 GHz at 7.93 GHz, and τf close to zero (∼0.12 ppm/°C). This enhanced performance was attributed to the optimization of internal variables, including enhanced relative density, homogeneous grain size, optimal phase fraction, and chemical ordering.

Synthesis of rGO-reinforced MgAl2O4 spinel composites by solid-state powder route mechanism: A comparative analysis between non-reinforced and rGO-reinforced spinel composites

Reduced Graphene Oxide (rGO)-reinforced MgAl2O4 spinel composite was successfully synthesized by a solid-state powder route mechanism via high-energy planetary ball milling of corresponding metal oxide precursors followed by a high-temperature single-stage sintering process. The effect of rGO on the homogeneity, phase development, morphology, chemical composition, rate of formation of spinel, and cation anti-site formation of the composites was methodically investigated. For comparison, a stoichiometric non-reinforced MgAl2O4 spinel was also synthesized. The addition of 0.2 wt% and 0.4 wt% of rGO as reinforcement increased the homogeneity of the ball-milled composite powder, with Polydispersity Index (PDI) values of 0.19 and 0.15 respectively, as compared to 0.24 obtained in non-reinforced spinel composite. The X-ray diffraction pattern and IR spectrum of 1650 °C sintered composites confirmed the formation of highly crystalline phases with spinel structure. The microstructural analysis revealed that the addition of rGO led to a reduction in porosity and improved the process of sintering. Calorimetric studies showed that spinelization started to occur at 858 °C and 880 °C for 0.2 wt% and 0.4 wt% rGO-reinforced composites respectively, which was faster than non-reinforced composite. 27Al solid-sate nuclear magnetic resonance (SS-NMR) analysis depicted that ceramic composite reinforced with rGO exhibited lesser inversion parameter of 0.09 (for 0.2 wt% rGO) and 0.055 (for 0.4 wt% rGO), as compared to 0.145 obtained in non-reinforced composite, indicating lesser cation anti-sites formation in rGO-reinforced spinel composite.

Self-Confined Dewetting Mechanism in Wafer-Scale Patterning of Gold Nanoparticle Arrays with Strong Surface Lattice Resonance for Plasmonic Sensing.

A self-confined solid-state dewetting mechanism is reported that can fundamentally reduce the use of sophisticated nanofabrication techniques, enabling efficient wafer-scale patterning of non-closely packed (ncp) gold nanoparticle arrays. When combined with a soft lithography process, this approach can address the reproducibility challenges associated with colloidal crystal self-assembly, allowing for the batch fabrication of ncp gold arrays with consistent ordering and even optical properties. The resulting dewetted ncp gold nanoparticle arrays exhibit strong surface lattice resonance properties when excited in inhomogeneous environments under normal white-light incidence. With these SLR properties, the sensitive plasmonic sensing of molecular interactions is achieved using a simple transmission setup. This study will advance the development of miniaturized and portable devices.

A solid-state Li-air battery: computational studies of interfaces and relevance to discharge mechanism.

There is much interest in developing new energy storage systems to replace currently available ones that mainly work based on Li-ion intercalations. One attractive area is the Li-air battery for which most of the research has involved liquid electrolytes. There have been few studies on the use of a solid electrolyte in a Li-air battery. Recently, we reported the successful use of a solid-state electrolyte in a Li-air battery resulting in a Li2O product and potentially much higher energy density than in a Li-air battery based on either a Li2O2 or LiO2 product (Science, 2023, 379, 499). In this paper we discuss how the discharge mechanism involved in this solid-state Li-air battery differs from that of a Li-air battery with a liquid electrolyte. The solid-state mechanism is further explored with density functional studies of various interfaces involving the discharge product. We discuss the relevance of the results to the discharge mechanism in the solid-state Li-air battery.

Dehydration promotes phosphoramidate-linked amino acidyl and peptido adenosine conjugates.

Cyclic nucleoside phosphates have been shown previously to be adequately activated to oligomerise under dry conditions. Herein, it is demonstrated that 3',5'-cyclic adenosine monophosphate (3',5'-cAMP) and glycine when subjected to dehydration under alkaline conditions form phosphoramidate-linked conjugates. Solid-state reaction mechanisms investigated by DFT suggest why the reaction does not occur efficiently in the aqueous phase.

Artificial neural networks in kinetic analysis of glass crystallization: The case of complex nucleation-growth mechanisms

The selected artificial neural networks were trained and tested to determine the kinetics of theoretically simulated signals for two overlapping independent nucleation-growth processes. Whereas the hybrid convolutional neural network did not perform well, the multilayer perceptron (MLP) showed great potential for the kinetic analysis of complex solid-state reactions and transformation mechanisms. In particular, the MLP architecture exhibited remarkable robustness with respect to the scatter in kinetic data as well as the ability to accurately deal with practically fully overlapping kinetic peaks. When trained on a full spectrum of double-process overlaps, the MLP architecture returned very precise estimates of the kinetic parameters during the testing phase despite the limited data sample used for some of the training. This level of accuracy was observed in the case of both overlapping processes being roughly similarly sized, and for the dominant process in the cases of the two processes being largely disproportionate in magnitude.