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Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

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All sourcesNASA NTRSDOE OSTI
DOE OSTI2022

Determination of physically based pseudo-Voigt powder diffraction profile terms from the fundamental parameters approach

In this study, a methodology is developed where a fundamental parameters approach (FPA) description of a laboratory powder diffraction instrument (configured in divergent-beam Bragg–Brentano geometry) is used to determine GSAS-II profile parameters for peak asymmetry and instrumental peak widths. This allows the instrumental contribution to peak shapes to be robustly determined directly from a physical description of the instrument, even though GSAS-II does not directly implement FPA for peak shape computation. The FPA-derived parameters can be used as the starting point for instrument characterization, or to characterize sample broadening without the use of a standard to determine the instrument profile function. This new method can facilitate generation of training sets for machine learning. A plot is generated that shows the differences between the two approaches, demonstrating upper bounds for the accuracy of the GSAS-II profile model for a particular instrumental configuration.

47 OTHER INSTRUMENTATION↗
DOE OSTI2016

The result of synthesis analysis of the powder TiO{sub 2}/ZnO as a layer of electrodes for dye sensitized solar cell applications

This study has been conducted synthesis of TiO{sub 2} nanoparticle powders and ZnO nanoparticle powder into a paste to be in this research, dye-sensitive solar cells (DSSC) was produced by TiO{sub 2} nanopowder and ZnO nanopowder synthesis to make paste that is applied as electrode. This electrode works based on photon absorbed by dye and transferred to different composition of TiO{sub 2}/ ZnO particle. Properties of DSSC are affected by fabrication method, parameter and dimension of TiO{sub 2} / ZnO nanoparticles, technique and composition of TiO{sub 2} / ZnO paste preparation is important to get the higher performance of DSSC. Doctor blade is a method for electrode coating on glass substrate. The electrode was immersed into dye solution of Z907 and ethanol. From the experiment, the effect of TiO{sub 2} and ZnO nanopowder mixture for electrode was investigated. XRD characterization show anatase and rutile phase, which sintered TiO{sub 2}/ZnO has intensity more than 11,000. SEM characterization shows the composition of 20% TiO{sub 2} / 80% ZnO has better porosity. Higher efficiency that is investigated by I-V measurement using Sun Simulator.

71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSIC↗
DOE OSTI2018

Phase Transformation Mechanism of Li-Ion Storage in Iron(III) Hydroxide Phosphates

Many ion storage compounds used for electrodes in Li-ion batteries undergo a first order phase transformation between the Li-rich and Li-poor end-members during battery charge and discharge. This often entails large transformation strains due to lattice misfits, which may hamper charge and discharge kinetics. Iron(III) hydroxide phosphate, Fe 2–y (PO 4 )(OH) 3–3y (H 2 O) 3y–2 is a promising new cathode material with high Li-ion storage capacity, low production costs and low toxicity. Previous reports on this material indicate that the Li-ion intercalation and extraction in this material is accompanied by a second-order solid solution transformation. However, direct information about the transformation mechanism in Fe 2–y (PO 4 )(OH) 3–3y (H 2 O) 3y–2 is lacking, and several details remain unclear. In this work, Fe 2–y (PO 4 )(OH) 3–3y (H 2 O) 3y–2 is prepared by hydrothermal synthesis and characterized structurally, morphologically and by electrochemical analysis (galvostatic cycling and cyclic voltammetry). A wide range of synthesis conditions is screened, which provides information about their correlation with chemical composition, crystallite size, particle morphology and electrochemical performance. The phase transformation mechanism of selected materials is investigated through synchrotron radiation powder X-ray diffraction collected during galvanostatic discharge–charge cycling. Furthermore, this confirms a complete solid solution transformation both during Li-insertion (discharge) and -extraction (charge), but also reveals a highly anisotropic evolution in lattice dimensions, which is linked to an irreversible reaction step and the high vacancy concentration in Fe 2–y (PO 4 )(OH) 3–3y (H 2 O) 3y–2 .

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2024

Critical Review of LPBF Metal Print Defects Detection: Roles of Selective Sensing Technology

The integrative potential of LPBF-printed parts for various innovative applications depends upon the robustness and infallibility of the part quality. Eliminating or sufficiently reducing factors contributing to the formation of defects is an integral step to achieving satisfiable part quality. Significant research efforts have been conducted to understand and quantify the triggers and origins of LPBF defects by investigating the material properties and process parameters for LPBF-printed geometries using various sensing technologies and techniques. Frequently, combinations of sensing techniques are applied to deepen the understanding of the investigated phenomena. The main objectives of this review are to cover the roles of selective sensing technologies by (1) providing a summary of LPBF metal print defects and their corresponding causes, (2) informing readers of the vast number and types of technologies and methodologies available to detect defects in LPBF-printed parts, and (3) equipping readers with publications geared towards defect detection using combinations of sensing technologies. Due to the large pool of developed sensing technology in the last few years for LPBF-printed parts that may be designed for targeting a specific defect in metal alloys, the article herein focuses on sensing technology that is common and applicable to most common defects and has been utilized in characterization for an extended period with proven efficiency and applicability to LPBF metal parts defect detection.

36 MATERIALS SCIENCE↗
DOE OSTI2022

Ultrasonic Testing (UT) and Computed Tomography (CT) Comparative Scanning of Proposed Additive Manufacturing Reference Standard

This report presents qualitative results of ultrasonic full matrix capture/total focusing method (FMC/TFM) scanning of two series of blocks, additively manufactured by powder bed fusion, containing a variety of internal features and structures that would not be achievable by conventional manufacturing techniques. The purpose of the first series of additively manufactured (AM) blocks was to explore the possibility of building calibration blocks for FMC/TFM ultrasonic testing (UT). It was confirmed that AM is a suitable candidate for generation of unusual and novel reflector forms, such as rotating slots, purposely embedded voids, and tapering holes, and that FMC/TFM was very capable of characterizing them. The intended use of the second series of AM blocks was as UT reference blocks to characterize the AM process quality or the interrogating UT technique. The larger block in this series was scanned from multiple faces, using multiple UT methods (conventional UT and FMC/TFM) and X-ray computed tomography for comparative purposes. The performance of each method was quantified by a metric corresponding to the detection limit of each feature, and the quantitative results are discussed.

36 MATERIALS SCIENCE↗
DOE OSTI2021

Characterization of injection and confinement improvement through impurity induced profile modifications on the Wendelstein 7-X stellarator

Pulsed injections of boron carbide granules into Wendelstein 7-X stellarator (W7-X) plasmas transiently increase the plasma stored energy and core ion temperatures above the reference W7-X experimental programs by up to 30%. In a series of 4 MW electron cyclotron resonance heating experiments, the PPPL Probe Mounted Powder Injector provided 50 ms bursts of 100 μm granules every 350 ms at estimated quantities ranging from approximately 1 mg/pulse to over 30 mg/pulse. For each injection, the stored energy was observed to initially drop and the radiated power transiently increased, while the radial electron density profile rose at the edge as material was assimilated. Once the injected boron carbide was fully absorbed, the density rise transitioned to the core while the stored energy increased above the previous baseline level by an amount linearly correlated with the injection quantity. During the injection, the ion temperature gradient steepened with peak core ion temperatures observed to increase from a nominal 1.7 keV to over 2.6 keV for the largest injection amounts. Enhanced performance is accompanied by a reversal of the radial electric field at ρ < 0.3, indicating that the core transport has switched to the ion root. These observations are suggestive of a change in transport and provide further evidence that externally induced profile modifications provide a possible path to enhanced W7-X performance metrics.

70 PLASMA PHYSICS AND FUSION TECHNOLOGY↗
DOE OSTI2016

Syntheses, structures and photoluminescent properties of Zn(Ⅱ)/Co(Ⅱ) coordination polymers based on flexible tetracarboxylate ligand of 5,5′-(butane-1,4-diyl)-bis(oxy)-di isophthalic acid

Three new mixed-ligand metal-organic frameworks based on 5,5′-(butane-1,4- diyl)-bis(oxy)-diisophthalic acid and transitional metal cations with the help of two ancillary bridging N-donor pyridyl and imidazole linkers, [Zn(L){sub 0.5}(4,4′-bpy)]·2(H{sub 2}O) (1), [M(L){sub 0.5}(bib)]·4(H{sub 2}O) (M = Zn (2), Co (3)), (4,4′-bpy=4,4′–bipyridine, bib=1,4-bis (1H-imidazol-1-yl)-butane), have been synthesized under solvothermal conditions. Their structures and properties were determined by single-crystal and powder X-ray diffraction analyses, IR spectra, elemental analyses and thermogravimetric analyses (TGA). Compounds 1–3 display a 3D 3-fold interpenetrated frameworks linked by the L{sup 4−} ligands, ancillary N-donor linkers and the free water molecules in the crystal lattice. Topological analysis reveals that 1–3 are a (4,4)-connected bbf topology net with the (6{sup 4}·8{sup 2})(6{sup 6}) topology. The effects of the L{sup 4−} anions, the N-donor ligands, and the metal ions on the structures of the coordination polymers have been discussed. Furthermore, luminescence properties and thermogravimetric properties of these compounds were investigated. - Graphical abstract: Three new compounds of MOFs have been prepared and characterized. The luminescence properties and thermogravimetric properties of compounds were investigated. Display Omitted.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2022

Carbon nanotube (CNT) reinforced 316L stainless steel composites made by laser powder bed fusion: Microstructure and wear response

Carbon nanotube (CNT) reinforced 316L stainless steel (SS) composites were fabricated by laser powder bed fusion (LPBF) additive manufacturing (AM). This study focuses on microstructure evolution, hardness, and wear behavior. The wear behavior for AM 316L SS and 1 wt% CNT/316L SS was studied by a dry sliding test under normal loads of 10, 15, and 25 N. The addition of CNT to 316L SS led to the change of solidification mode from cellular/columnar to dendritic growth, producing grain refinement. Nanoscale dendrites were observed. Although TEM characterization confirmed the existence of CNT in cell interior, most CNT were damaged, resulting in carbon material segregation along cellular/dendritic boundaries. The wear rate was found dramatically decreased due to the improved hardness. Compared to the adhesive and abrasive wear in AM 316L SS, the wear mechanism of CNT/316L composite was adhesion and oxidative wear. Furthermore, enhanced cellular/dendritic boundary strengthening by carbon segregation was the main strengthening mechanism of CNT/316L composite.

36 MATERIALS SCIENCE↗
DOE OSTI2017

Structure and decomposition of the silver formate Ag(HCO{sub 2})

Crystal structure of the silver formate Ag(HCO{sub 2}) has been determined (orthorhombic, sp.gr. Pccn, a=7.1199(5), b=10.3737(4), c=6.4701(3)Å, V=477.88(4) Å{sup 3}, Z=8). The structure contains isolated formate ions and the pairs Ag{sub 2}{sup 2+} which form the layers in (001) planes (the shortest Ag–Ag distances is 2.919 in the pair and 3.421 and 3.716 Å between the nearest Ag atoms of adjacent pairs). Silver formate is unstable compound which decompose spontaneously vs time. Decomposition was studied using Rietveld analysis of the powder diffraction patterns. It was concluded that the diffusion of Ag atoms leads to the formation of plate-like metal particles as nuclei in the (100) planes which settle parallel to (001) planes of the silver formate matrix. - Highlights: • Silver formate Ag(HCO{sub 2}) was synthesized and characterized. • Layered packing of Ag-Ag pairs in the structure was found. • Decomposition of Ag(HCO{sub 2}) and formation of metal phase were studied. • Rietveld-refined micro-structural characteristics during decomposition reveal the space relationship between the matrix structure and forming Ag phase REPLACE with: Space relationship between the matrix structure and forming Ag phase.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2018

SAPO-34/5A Zeolite Bead Catalysts for Furan Production from Xylose and Glucose

SAPO-34 zeolite crystals were grown on zeolite 5A beads, characterized, and then utilized to produce furfural from xylose and 5-hydroxymethylfurfural (HMF) from glucose. The SAPO-34/5A bead catalysts resulted in moderate furfural and HMF yields of 45% from xylose and 20% from glucose (463 K; 3 h) and were easier to recover than the SAPO-34 powder catalyst. At 463 K, the SAPO-34/5A beads were more selective than 0.02 M sulfuric acid for producing HMF and, unlike the sulfuric acid system, no levulinic acid was formed. The SAPO-34/5A bead catalysts had no significant loss in activity after three rounds of recycle when water washed or heated overnight between reactions; however, the heat-treated beads did show signs of thermal stress after the second reuse. The SAPO-34/5A bead catalysts show promise for dehydration reactions to produce furfural and HMF from xylose and glucose, respectively, and adapting the catalyst and the support bead could lead to even higher selectivities and yields.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2016

Structural characterization of FeVO{sub 4} synthesized by co-precipitation method

A Low temperature method for synthesizing triclinic FeVO{sub 4} nanoparticles is manifested through co-precipitation method. Three precursor materials taken for the synthesis are Iron Nitrate, Ammonium Metavanadate and NaOH along with DI water. The attained precipitate was dried at 100°C for overnight and calcined at different temperatures ranging from 400°C - 650°C. The achieved powdered materials are studied through X-ray diffraction and found to be in pure single phase of P-1 space group symmetry. The crystallite size measured through Scherrer’s method is in found to be in the range of 40-60 nm. Raman spectroscopic studies were carried out at room temperature. Raman spectra is in agreement with the reported structural data of FeVO{sub 4}.

77 NANOSCIENCE AND NANOTECHNOLOGY↗
DOE OSTI2018

Sol-gel synthesis of Mn1.5Co1.5O4 spinel nano powders for coating applications

Highlights: • Nano powder of Mn/Co spinel, applicable to solid oxide fuel cell, is synthesized. • The sol-gel synthesis of nanocrystalline Mn{sub 1.5}Co{sub 1.5}O{sub 4} spinel is investigated. • Sol-gel annealing temperature, time, and metal-to-citrate ratio are evaluated. • The optimum conditions for producing dual phase of Mn{sub 1.5}Co{sub 1.5}O{sub 4} are achieved. - Abstract: Mn{sub 1.5}Co{sub 1.5}O{sub 4} oxide spinels are widely used as protective coatings for stainless steel interconnects within planar solid oxide fuel cell stacks. Containing both cubic and tetragonal crystalline phases, these Mn/Co oxide spinels exhibit favorable thermal stability and electronic conductivity for the SOFC interconnect application. Slurry-based coating applications of Mn/Co oxides require precursor powders, which can benefit from being nano-structured. In this study, the sol-gel synthesis of nanocrystalline Mn{sub 1.5}Co{sub 1.5}O{sub 4} spinel is investigated. The decomposition of sol-gel precursors, as well as the crystalline phase structures and microstructures of the product Mn{sub 1.5}Co{sub 1.5}O{sub 4} are characterized by differential thermal and thermogravimetric (DTA/TG) analysis, X-ray diffraction (XRD), and transmission electron microscopy (TEM). The effects of various sol-gel annealing temperatures (T), treatment times (t), and citrate-to-metal ratios (Rc) are evaluated. Results suggest that nanocrystalline Mn{sub 1.5}Co{sub 1.5}O{sub 4} spinel can be synthesized around 1050 °C, and that T = 1050 °C, t = 6 h and Rc = 2 are optimum conditions for producing the smallest grain size. Image analysis of TEM results shows that the size of Mn{sub 1.5}Co{sub 1.5}O{sub 4} crystallites increases with increasing temperature, with average particle sizes ranging from ∼70 nm to ∼1 μm. Selected area diffraction pattern (SADP) of Mn{sub 1.5}Co{sub 1.5}O{sub 4} spinel synthesized at 800 °C confirms the dual (cubic/tetragonal) structure of Mn{sub 1.5}Co{sub 1.5}O{sub 4}.

77 NANOSCIENCE AND NANOTECHNOLOGY↗
DOE OSTI2022

USE OF TWO-PISTON SPLAT QUENCHING TO INVESTIGATE & CHARACTERIZE THE IMPACT OF COMPOSITIONAL VARIATIONS ON RAPID SOLIDIFICATION MICROSTRUCTURES & SUB-MICROSCALE FEATURES IN STAINLESS STEEL ALLOY.

The objective of this dissertation was to use two-piston splat quenching (SQ) to investigate the impact of compositional modifications on the solidification and microstructure of rapidly solidified austenitic stainless steels (SS) and to demonstrate the ability of SQ to quickly and effectively simulate rapid solidification conditions similar to those found in powder bed fusion (PBF) additive techniques. PBF techniques like laser powder bed fusion (LPBF) are being implemented across a breadth of research and industrial applications to create parts with complex geometries and performance capabilities while pushing the current limits of processing conditions and understanding of material systems. In this work, SQ was used to experimentally produce rapid solidification in 20+ unique austenitic SS compositions with systematic variations of the chrome and nickel equivalency ratio (Cr/Nieq) through targeted compositional modifications. From the targeted change of Cr, Ni, and Mo concentrations in rapidly solidified SS alloys, the ferrite solidification mode was found to be the primary solidification mode at significantly lower Cr/Nieq than previously predicted for RS. Also, decreasing concentrations of Fe at a constant Cr/Nieq ratio (i.e., different Fe isopleths), or increased Mo concentrations at a constant Cr/Nieq ratio were found to suppress the ferrite to austenite massive transformation when compared to alloys with lower concentrations at the same Cr/Nieq. Using an established empirical relationship between cell size and cooling rate, the SQ technique was estimated to produce cooling rates between 106 and 108 K/s. Thermal gradients were extracted from 2-D heat transfer simulations of the SQ solidification event and used with these cooling rates to produce solidification rate estimates for SQ which were between 0.4-1.6m/s. The primary solidification mode was observed to be the determining factor in which elements segregated to the cell boundaries during RS, for which Cr and Mo were the main elements to segregate during primary austenite solidification and Ni during primary ferrite solidification. Finally, the solidification rates and conditions produced by SQ experiments resulted in similar microstructures, features, and microsegregation to what was found in LPBF samples of the same feedstock.

Hasenbusch, Zachary↗
DOE OSTI2023

Accelerating Additive Manufacturing Process Design for Energy Conversion Materials using In-situ Sensing and Machine Learning

One promising candidate for manufacturing of the bismuth Telluride thermoelectric legs is laser powder bed fusion (LPBF) additive Manufacturing (AM). AM processing parameters highly influence the material properties, however current processing parameter development methods in AM are costly and time consuming. In-situ sensors allow for the capture of physically relevant process information on a layer-by-layer basis and will be used to aide process development. To optimize the AM process for the best thermoelectric performance, process variables, in-situ process sensor data and ex-situ material characterization data are collected. Several different interpretable machine learning (ML) approaches are used, and the performance of each method are assessed. Significant input process variables include laser focus, hatch spacing and laser power. The best performing models are used to determine the manufacturing parameters that maximize the power factor. AM of bismuth telluride material provides the ability to create complex geometries enabling more efficient energy conversion.

30 DIRECT ENERGY CONVERSION↗
DOE OSTI2020

3D Ion-Conducting, Scalable, and Mechanically Reinforced Ceramic Film for High Voltage Solid-State Batteries

Concerning the safety aspects of Li+ ion batteries, an epoxy-reinforced thin ceramic film (ERTCF) is prepared by firing and sintering a slurry-casted composite powder film. The ERTCF is composed of Li + ion conduction channels and is made of high amounts of sintered ceramic Li 1+ x Ti 2-x Al x (PO 4 ) 3 (LATP) and epoxy polymer with enhanced mechanical properties for solid-state batteries. The two- and three-dimensional characterizations are conducted not only for showing continuous Li+ ion channels thorough LATP ceramic channels with over 10-4 S cm-1 of ionic conductivity but also to investigate small amounts of epoxy polymer with enhanced mechanical properties. Solid-state Li + ion cells are fabricated using the ERTCF and they show initial charge–discharge capacities of 139/133 mAh g -1 . Furthermore, the scope of the ERTCF is expanded to high-voltage (>8 V) solid-state Li + ion batteries through a bipolar stacked cell design. Hence, it is expected that the present investigation will significantly contribute in the preparation of the next generation reinforced thin ceramic film electrolytes for high-voltage solid-state batteries.

25 ENERGY STORAGE↗
DOE OSTI2025

Optical vibrational spectroscopic signatures of ammonium diuranate process parameters

Ammonium diuranate (ADU) is commonly encountered in the nuclear fuel cycle; however, previous investigations have shown that ADU is a complex mixture of distinct compounds. Moreover, production parameters are known to heavily influence the composition of the resulting ADU. Here, we examine four samples of ADU prepared at Oak Ridge National Laboratory (ORNL), and one sample of ADU made at Pacific Northwest National Laboratory (PNNL), with the goal of further characterizing and elucidating the effect of processing parameters such as stir rate, strike direction, and temperature on material composition. Process parameters during ADU precipitation at ORNL and PNNL were well documented, and we relate process variables to optical vibrational spectroscopic signatures observed using Raman and infrared (IR) spectroscopy. In addition, powder X-ray diffraction (PXRD) reveals differences in the solid-phase composition of ADU precipitates, but we find that the primary phase is similar to the uranyl oxyhydroxyhydrate mineral metaschoepite. Despite the significant phase contributions of a metaschoepite-like phase, spectroscopic evidence of both nitrate and ammonium are observed for all samples. To gain a more holistic understanding of spectroscopic features of process parameters in ADU, principal component analysis (PCA) is employed and results in observable signatures that relate to the stir rate used during synthesis. These results provide further information about the process-dependence of ADU precipitate composition.

11 NUCLEAR FUEL CYCLE AND FUEL MATERIALS↗
DOE OSTI2022

Crystal Chemistry and Thermodynamics of HREE (Er, Yb) Mixing in a Xenotime Solid Solution

Rare earth elements (REEs), the 15 naturally occurring lanthanides plus yttrium and scandium, are ubiquitously used in modern life as they are critical components of many advanced devices and technologies. However, the demand for REEs is not equal, with the heavy rare earth elements (HREEs) having a higher demand. Xenotime (HREEPO 4 ) is an important HREE ore mineral and globally is an economical source of HREE. Most of the crystallographic and thermodynamic properties of xenotime endmembers have been elucidated by calorimetric, solubility, and high-pressure studies. Yet, in natural systems, endmembers are rarely encountered, and instead, REE solid solutions are more commonly observed. Here, we characterize the crystal chemistry, thermodynamics of HREE mixing, and high-temperature material behaviors and thermochemistry of a synthetic erbium (Er)-ytterbium (Yb) binary xenotime solid solution (Er (x) Yb (1-x) PO 4 ) using a suite of experimental techniques, including X-ray fluorescence spectroscopy, synchrotron X-ray powder diffraction implemented with Rietveld analysis, Fourier transform infrared spectroscopy coupled with attenuated total reflectance, Raman spectroscopy, thermogravimetric analysis coupled with differential scanning calorimetry, and high-temperature oxide melt drop solution calorimetry. Our results shed light on the formation of natural xenotimes and lay the foundation for their industrial applications as thermal coating materials.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗