Soft magnetic composites (SMCs) have gained interest for applications associated with passive electronics and motor components due to their low total core losses and affordability. However, a need has arisen for SMCs that can operate at high frequencies with high magnetizations, leading to a search for novel materials that can breach these frequency thresholds while maintaining a high saturation magnetic polarization (Js) without ceding to core losses. Specifically, the iron–cobalt alloy exhibits a high Js value, but possesses a low resistivity (ρ), impeding its integration into electric motors and machinery. However, by employing an insulating layer, the resistivity of the material can be increased. Seeking a facile synthesis to bolster the resistivity of FeCo SMCs, we investigated an insulating phosphate coating at two weight percents: 0.1 and 0.2 wt

This study investigates the inert Hugoniot response, mechanical ignition, and reaction dynamics of Ni ( V ) + Al multilayers during longitudinal, laser-driven shock compression experiments. Ni ( V ) + Al multilayers, known for their self-propagating exothermic reactions, were subjected to longitudinal stresses exceeding 50 GPa using the laser shock facility within the Dynamic Compression Sector (DCS) at the Advanced Photon Source (APS). In situ x-ray diffraction (XRD) revealed that Ni(V) and Al were not in equilibrium during compression, with stress discrepancies attributed to twinning, grain structure effects, and/or dislocation density. However, the measured inert Hugoniot closely matched prior experimental and computational studies, confirming the utility of XRD for measuring the equation of state of thin, complex materials. Additionally, reaction was observed at significantly higher stresses than reported previously using laser-launched flyers. This discrepancy suggests a strong influence of externally imposed shear stress on reaction thresholds, which likely arose from deviations in flyer planarity during past experiments. Full reaction of the multilayer occurred within 40 ns after shock-wave passage, evidenced by complete melting of the constituents. Eulerian hydrocode simulations replicated experimental conditions, providing insights into equilibrium dynamics and experimental artifacts. The results highlight how even small shear forces facilitate ignition in Ni ( V ) + Al multilayers at lower stresses.

Combinatorial synthesis approaches are often coupled with high-throughput characterization techniques so as to effectively facilitate accelerated material discovery. In this study, a rapid and nondestructive method based on x-ray reflectivity (XRR) was developed to measure the density of combinatorial thin films without any prior microstructural assumptions. Utilizing automated methods, x-ray reflectograms were acquired from 560 combinatorial Pt-Au, 112 elemental Pt, and 112 elemental Au thin films fabricated on Si (100) wafers (112 deposition areas per wafer), and these datasets were evaluated using a unique analysis approach to rapidly deduce thin film densities. Traditionally, complex fitting procedures are applied to XRR to estimate the critical angle θc (angle at or below which total reflection occurs), which can then be used to calculate the film density. This study demonstrates an alternative, rapid method—using an indirect surrogate angle θs (instead of θc) that is numerically calculated (without any curve-fitting) as the minimum in the first derivative of the acquired XRR profiles. It was found that density values estimated using θs and adjusted with a systematic offset were generally in agreement with the traditional curve-fitting method, with typical average error percentages peaking at < 2

The magnetostrictive response of a Terfenol-D pellet was measured via a laboratory-based X-ray diffractometer. X-ray diffraction patterns were collected from the pellet sample with and without the presence of an applied magnetic field (~30 mT) generated by placing a large magnet under the pellet. A standard reference material, Silicon 640c, was employed as an internal standard. Magnetostriction values of 323 and 227 ppm Δ l / l were determined for the (104) and (110) indexed peaks, respectively, assuming a rhombohedral structure for Terfenol-D. A threshold noise level value of ~20 to 30 ppm Δ l / l was suggested based on before/after measurements in the absence of the applied field. No clear evidence of domain wall rotation was detected via changes in relative intensities of diffraction peaks in the presence of the applied magnetic field.

The dry reforming of methane reaction is a promising means to convert two potent greenhouse gases, methane and carbon dioxide, into industrially valuable synthesis gas. However, the presence of reducing gases and high operating temperatures degrade conventional nickel catalysts via excessive coke formation and particle sintering. These catalysts are not readily regenerated because the oxidative heat treatments employed to remove coke further promote active particle sintering. Herein, we designed high entropy aluminate spinel oxides (MAl2O4 where M = Co, Mg, Ni, and divalent site vacancies in nominal equimolar concentration) as selective and regenerable reforming catalysts. Under reaction conditions, reducible nickel and cobalt cations exsolved from the spinel lattice to form highly selective bimetallic particles on the oxide surface. Instead of sintering, these particles uniquely redissolved back into the aluminate lattice upon reoxidation and regained the original spinel structure. This phenomenon is ascribed to entropic stabilization, wherein an increase in configurational entropy creates a thermodynamic driving force for redispersing supported metal particles back into the multi‐cationic oxide structure, which was not seen on the NiAl2O4 sample where Ni sintered during oxidation to burn off coke. High entropy materials thus provide a unique mechanism of regeneration, which is inaccessible in conventional catalysts.

The Na+ super ion conductor (NaSICON, Na1+ xZr2SixP3- xO12) is a solid electrolyte well-known for fast, selective Na+ transport at low temperatures, uniquely enabling sodium-based batteries. Producing high-quality NaSICON from solid-state methods, especially when cost-effective, potentially hygroscopic precursors are used, is not trivial. To understand and eliminate the influence of humidity during processing, a scheme was developed to reproducibly yield a high Na+ conductivity (3.75 mS/cm at 25 degrees C, 81.7 mS/cm at 150 degrees C), high density (97%), and machinable NaSICON without the use of binders, sintering aids, or dopants. Controlled humidity studies over 20%-50% RH coupled with thermal, structural, and electrical analysis reveal that calcination temperatures < 1000 degrees C leave NaSICON processing susceptible to water absorption at > 20% RH due to the presence of hygroscopic Na3PO4 and Na2CO3 during shaping, pressing, and sintering. Water absorption results in NaSICON with lower densities, machinability, and Na+ conductivity, due to impaired intergranular Na+ transport. At the other extreme, fully converting precursor to the NaSICON phase at 1230 degrees C before pressing and sintering leads to poor conductivity and density. By calcining at 1000 degrees C, excellent quality NaSICON may be produced under a range of laboratory environments, enabling low-cost production of high-conductivity, machinable NaSICON necessary the ever-growing energy storage market.

Advances in Sandia's proprietary software ORION (formerly CAD2VR) and its CrystalVR plug-in have provided new ways to interact with 3-D crystal structures in a virtual reality (VR) environment. Users are now able to visualize thermal ellipsoid data alongside ball-and-stick and wireframe models. CrystalVR can read .cif, .res, and .pdb file formats, thereby broadening the scope of scientific exploration and analysis in both desktop and virtual reality settings. For portability, our team utilizes Looking Glass displays to present 3-D molecular data. A plug-in is in development for seamless export from ORION to the Looking Glass file format. Our recently published structure 2,9-diamino5,6,11,12-tetrahydrodibenzo[a,e]cyclooctene (DOI: 10.1107/S2056989024004468) is featured in both ORION desktop mode and on a Looking Glass Portrait. Advances in Sandia's proprietary software ORION (formerly CAD2VR) and its CrystalVR plug-in have provided new ways to interact with 3-D crystal structures in a virtual reality (VR) environment. Users are now able to visualize thermal ellipsoid data alongside ball-and-stick and wireframe models. CrystalVR can read .cif, .res, and .pdb file formats, thereby broadening the scope of scientific exploration and analysis in both desktop and virtual reality settings. For portability, our team utilizes Looking Glass displays to present 3-D molecular data. A plug-in is in development for seamless export from ORION to the Looking Glass file format. Our recently published structure 2,9-diamino5,6,11,12-tetrahydrodibenzo[a,e]cyclooctene (DOI: 10.1107/S2056989024004468) is featured in both ORION desktop mode and on a Looking Glass Portrait.

We report the lattice parameters and cell volume for cristobalite powder added at 35 wt% to Ba-Al-Silicate glass (CGI930) as reflowed bulk glass bars where the embedded cristobalite phase is constrained within the glass matrix. Analysis confirms that the room temperature lattice parameters and cell volume obtained for the bulk glass–ceramic are larger compared with single-phase cristobalite powders. The increased volume of the cristobalite phase in a glass matrix is driven by tensile stresses developed at the interface between the cristobalite and matrix glass phase, and this stress impacts the phase transition temperature and thermal hysteresis of the cristobalite phase. In situ high-temperature measurements confirm that the tetragonal to cubic α–β phase transformation of the cristobalite phase within the glass matrix is ~195 °C with complete suppression of hysteresis behavior. In contrast, bulk glass–ceramic material ground to a powder form displays the expected thermal hysteresis behavior and more comparable phase transition temperatures of 245 °C on heating and 220 °C on cooling. Isothermal holds at varying temperatures above or near the α–β phase transition suggest that the cristobalite phase does not undergo significant relaxation within the matrix phase to reduce accumulated stress imposed by the constraining matrix glassy phase.

Selective adsorption of anions from aqueous solutions is essential to many industrial and remediation applications. A novel anion sorbent was developed using hybrid glycoboehmite (GB) synthesized from 1,4-butanediol and potassium hydroxide mineralizer. GB materials were further functionalized through Ni2+ adsorption from aqueous solutions. The adsorption capacity of GB for Ni2+ was found to be 2 to 5 times greater than that for Mg2+ or Ca2+, and 12 times higher than that of simple boehmite normalized to the surface area. Relative to GB, nickel-functionalized GB (Ni-GB) exhibits favorable adsorption properties for arsenate and iodide with much improved partitioning coefficient values (KD) of ~ 6400 and 43 mL/g respectively. Experimental characterization along with classical and ab initio molecular dynamics simulations offers insight into the ion adsorption mechanism.

Soft magnetic materials play key roles in the flow of energy in electrically driven machines and power conversion electronics, and there is a great need for improvements in their magnetic properties to provide the right combination of high saturation magnetization, low coercivity, and high permeability. Most phases of iron nitride (Fe x N) are soft magnetic materials with these characteristics, but they exist as numerous phases which are not all stoichiometric compounds. While the production and magnetic properties of the different phases of bulk iron nitride are well known, accessing phase‐pure nanoscale iron nitride consistently remains a challenge. Most methods for the synthesis of iron nitride nanoparticles require complicated apparatus to achieve high‐temperature nitriding of nanoparticle precursors with gaseous nitrogen sources such as ammonia. The first solution‐phase metathesis reaction between FeCl 3 and Li 3 N in oleylamine is developed to directly synthesize Fe 2 N/Fe 3 N nanoparticles, requiring only a fume hood, glove box, standard chemistry laboratory glassware, and equipment. The ≈10–15 nm spheres display nearly soft magnetic behavior with a saturation magnetization ≈50–60 A m 2 kg −1 , coercivities between 40–50 kA m −1 , and susceptibility values from 0.0001–0.0006 m 3 kg −1 , well within the ranges reported with other published Fe x N nanoparticle synthesis methods.

Soft magnetic materials play key roles in the flow of energy in electrically driven machines and power conversion electronics, and there is a great need for improvements in their magnetic properties to provide the right combination of high saturation magnetization, low coercivity, and high permeability. Most phases of iron nitride (FexN) are soft magnetic materials with these characteristics, but they exist as numerous phases which are not all stoichiometric compounds. While the production and magnetic properties of the different phases of bulk iron nitride are well known, accessing phase-pure nanoscale iron nitride consistently remains a challenge. Most methods for the synthesis of iron nitride nanoparticles require complicated apparatus to achieve high-temperature nitriding of nanoparticle precursors with gaseous nitrogen sources such as ammonia. The first solution-phase metathesis reaction between FeCl3 and Li3N in oleylamine is developed to directly synthesize Fe2N/Fe3N nanoparticles, requiring only a fume hood, glove box, standard chemistry laboratory glassware, and equipment. The approximate to 10-15 nm spheres display nearly soft magnetic behavior with a saturation magnetization approximate to 50-60 A m2 kg-1, coercivities between 40-50 kA m-1, and susceptibility values from 0.0001-0.0006 m3 kg-1, well within the ranges reported with other published FexN nanoparticle synthesis methods.

MoS2 coatings are used extensively in aerospace and defense applications due to their ultralow friction and high wear resistance. Burnished and resin-bonded MoS2 coatings are commonly used in these applications due to simplicity in deposition and history of use, despite issues with consistency in coating properties and performance. Physical vapor deposition (PVD) of MoS2 thin films has emerged as a process alternative in the past 50 years, promising far greater control over film structure and composition but at a greater cost. Despite PVD's benefits, hesitance to adoption persists in high-consequence applications, not only due to increased costs but variability in resulting coating properties. These variations in properties and subsequent performance are in part due to the complexity of the PVD process and the sensitive interplay between coating process-structure-property relationships. This work aims to demystify the remaining uncertainties of the process-structure-property relationships in PVD MoS2. The microstructure and mechanical and tribological properties of 61 different PVD pure MoS2 coatings are examined herein. Emphasis has been placed on developing performance-based (i.e., hardness, modulus) metrics that can assess microstructural changes (density, orientation, and crystallinity) and be utilized to accelerate process development and coating optimization. Relationships established within suggest that nanoindentation hardness can be used to infer coating performance (i.e., wear rate) and properties (i.e., density, crystalline texture, and stoichiometry). Furthermore, this work demonstrates that PVD MoS2 coatings close to the theoretical density of MoS2 consistently have the best tribological performance and can be reliably identified by their hardness.

The cis- form of diaminodibenzocyclooctane (DADBCO, C16H18N2) is of interest as a negative coefficient of thermal expansion (CTE) material. The crystal structure was determined through single-crystal X-ray diffraction at 100 K and is presented herein.

Thin films composed of transition metal dichalcogenides such as molybdenum disulfide (MoS2) or tungsten disulfide (WS2) are well known for their solid lubricating behavior in dry environments such as space, but deteriorate rapidly in environments where oxygen is present. There have been many attempts over recent decades to improve MoS2 lubricating performance in humid environments by addition of metals such as titanium to the film. The additions have come in the form of co-sputtering with the MoS2, or formation of nano multilayer coatings. We have previously reported on the synthesis of MoS2 films by high-power ion beam ablation [Prasad et al, Matls. Lett. 65 (2010) 4-6]. The resulting films are observed to contain spheres of pure Mo of 10-100 nm size evenly dispersed throughout the similar to 1 mu m-thick film, a form of self-assembly not before seen in films produced by sputtering or by pulsed laser deposition (PLD). The remaining MoS matrix was observed to crystalize in situ under frictional contact into MoS2 with the basal planes orienting themselves in the direction of sliding underneath the wear surface. The present study concerns metal additions in the form of alternating layers with MoS2 deposited in between from an ablation target. The addition of Ti resulted in the extension of good tribological performance to humid air conditions, but the path to good performance appears to be relatively narrow. The same distributed Mo spheres were present in the new film, and similar self-assembled morphologies when V was substituted for the Ti, and when multilayers were formed of WS2 with Zr additions. It appears that addition of Ti resulted in improvements in mechanical film strength that contributed to the wear ability in humid conditions.

Physical vapor deposited (PVD) molybdenum disulfide (nominal composition MoS2) is employed as a thin film solid lubricant for extreme environments where liquid lubricants are not viable. The tribological properties of MoS2 are highly dependent on morphological attributes such as film thickness, orientation, crystallinity, film density, and stoichiometry. These structural characteristics are controlled by tuning the PVD process parameters, yet undesirable alterations in the structure often occur due to process variations between deposition runs. Nondestructive film diagnostics can enable improved yield and serve as a means of tuning a deposition process, thus enabling quality control and materials exploration. Grazing incidence X-ray diffraction (GIXRD) for MoS2 film characterization provides valuable information about film density and grain orientation (texture). However, the determination of film stoichiometry can only be indirectly inferred via GIXRD. The combination of density and microstructure via GIXRD with chemical composition via grazing incidence X-ray fluorescence (GIXRF) enables the isolation and decoupling of film density, composition, and microstructure and their ultimate impact on film layer thickness, thereby improving coating thickness predictions via X-ray fluorescence. We have augmented an existing GIXRD instrument with an additional X-ray detector for the simultaneous measurement of energy-dispersive X-ray fluorescence spectra during the GIXRD analysis. This combined GIXRD/GIXRF analysis has proven synergetic for correlating chemical composition to the structural aspects of MoS2 films provided by GIXRD. We present the usefulness of the combined diagnostic technique via exemplar MoS2 film samples and provide a discussion regarding data extraction techniques of grazing angle series measurements.

A thermally driven, micrometer-scale switch technology has been created that utilizes the ErH3/Er2O3 materials system. The technology is comprised of novel thin film switches, interconnects, on-board micro-scale heaters for passive thermal environment sensing, and on-board micro-scale heaters for individualized switch actuation. Switches undergo a thermodynamically stable reduction/oxidation reaction leading to a multi-decade (>11 orders) change in resistance. The resistance contrast remains after cooling to room temperature, making them suitable as thermal fuses. An activation energy of 290 kJ/mol was calculated for the switch reaction, and a thermos-kinetic model was employed to determine switch times of 120 ms at 560 °C with the potential to scale to 1 ms at 680 °C.

Sputter-deposited Pt-Au thin films have been reported to develop a hard, stable, nanocrystalline structure, yet little is known about how these characteristics vary with PtxAu1-x composition and process conditions. Toward this end, this document describes an extensive, combinatorial Pt-Au thin film library including characterized film compositions, structure, and properties. Complemented by kinematic Monte Carlo simulations of codeposition, a broad range of PtxAu1-x compositions (from x similar to 0.02 to 0.93) was first established by sputtering with varied magnetron powers and gun tilt angles. The produced films were subsequently interrogated using automated nanoindentation, x-ray reflectivity, x-ray diffraction, atomic force microscopy, surface profilometry, four-point probe sheet resistance techniques, and wavelength dispersive spectroscopy in order to determine how hardness, modulus, density, surface roughness, structure, and resistivity vary with film stoichiometry and process parameters. Combinatorial films displayed an assortment of properties with the hardness of some films exceeding values reported previously for this material system. High hardness, high modulus, and low resistivity were generally attained when using increased deposition energy and reduced angle-of-incidence processes. Overall, the research identified promising, new PtxAu1-x compositions for future study and pinpointed strategies for improved deposition.

Thermal degradation is a leading cause of automotive catalyst deactivation. Because high-entropy oxides are uniquely stabilized at high temperatures via an increase in configurational entropy, these materials may offer new mechanisms for preventing the thermal deactivation of precious metal catalysts. In this work, we evaluated platinum loaded on simple and high-entropy aluminate spinels (MAl2O4, where M = Co, Cu, Mg, Ni, or mixtures thereof) in carbon monoxide oxidation before and after aging at 800 °C. Pt supported on all simple spinels showed significant deactivation after thermal aging compared to the fresh samples, with T90 increasing by at least 60 °C. However, Pt on high-entropy spinels had nearly the same or better activity after aging, with T90 increasing by only 6 °C at most. During aging and reduction, copper exsolved from the spinel supports and alloyed with platinum. This interaction promoted low temperature oxidation activity, presumably through weakened CO binding, but did not prevent deactivation. On the other hand, Co, Mg, and Ni constituents promoted stronger CO bonding, as evidenced by apparent negative order kinetics and poor activity at low temperatures. High-entropy spinels, containing a variety of active metals, displayed synergetic reactant adsorption capacity and cooperative effects with supported platinum particles, which collectively prevented thermal deactivation.

Successful separation of cis- and trans-di­amino­dibenzo­cyclo­octane (DADBCO) allows the crystal structure solution of cis-DADBCO.