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All sources NASA NTRS DOE OSTI

DOE OSTI2018

Manufacturing and characterization of Ni-free N-containing ODS austenitic alloys

Ni-free N-containing oxide dispersion strengthened (ODS) austenitic alloys were manufactured by mechanical alloying (MA) followed by spark plasma sintering (SPS). The phase evolutions during milling under a nitrogen atmosphere and after sintering were studied by X-ray diffraction (XRD). Transmission electron microcopy (TEM) and contrast variation analysis (ACV), including small-angle neutron scattering (SANS) and ultra-small X-ray scattering (USAXS), revealed the existence of nanoparticles with a diameter of 3-51 nm for the samples sintered at 950 ºC. Sintering at 1000 ºC for 5 and 15 min caused slight growth and a significant coarsening of the nanoparticles, up to 70 nm and 128 nm, respectively. The ACV analysis indicated the existence of two populations of Y2O3, ε-martensite and MnO. The dispersive X-ray spectrometry (EDS) confirmed two kinds of nanoparticles, Y2O3 and MnO. The material was characterized by superior micro-hardness, of above 500 HV0.1.

36 MATERIALS SCIENCE↗

DOE OSTI2018

The Li{sup +} conducting composite based on LiTi{sub 2}(PO{sub 4}){sub 3} and Li{sub 3}BO{sub 3} glass

Highlights: • Addition of the LBO glass enhance total ion conductivity up to four orders of magnitude. • Transport of Li{sup +} could be attributed to two media: grains and grain boundaries. • Sintering temperature is the most influential factor affecting the σ{sub tot}. • Melting of the LBO above 700 °C supports the sintering process. - Abstract: The LiTi{sub 2}(PO{sub 4}){sub 3} based composites containing amorphous Li{sub 3}BO{sub 3} were formed and investigated by means of X–ray diffractometry, thermogravimetry, scanning electron microscopy, impedance spectroscopy and density methods. The study shows that when a polycrystalline LiTi{sub 2}(PO{sub 4}){sub 3} material is sintered with Li{sub 3}BO{sub 3} glass, the resultant ceramics exhibit very high total ion conductivity. The maximum conductivity of 1.43 × 10{sup −4} S cm{sup −1} at 30 °C was achieved for the LTP–0.3LBO material sintered at 900 °C compared to 5.15 × 10{sup −8} S cm{sup −1} of the ceramic LiTi{sub 2}(PO{sub 4}){sub 3}.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗

DOE OSTI2013

Characterization of 430L porous supports obtained by powder extrusion moulding for their application in solid oxide fuel cells

The characterization of 430L stainless steel planar porous supports obtained by powder extrusion moulding was performed in this work. A thermoplastic multicomponent binder based on high density polyethylene and paraffin wax was selected for the process. Green supports were shaped by extrusion moulding, and subsequently the binder was removed by a thermal cycle previously optimized. Sintering was carried out at different temperatures in low vacuum. Density of sintered parts was measured by Archimedes' method and porosity was also evaluated through a microstructural analysis by optical microscopy. The porosity degree of samples sintered at low temperature was close to 35% which is a very suitable value for their application in SOFCs. Tensile tests were carried out in order to determine mechanical strength as a function of porosity degree. Based on these results, the best feedstock composition and processing parameters were selected. The oxidation behaviour in static air at high temperature was studied, and formed oxides were characterized in a scanning electron microscope equipped with energy dispersive analysis of X-rays. X-ray diffraction experiments were performed in order to identify the formed oxides based on formula Fe{sub 2−x}Cr{sub x}O{sub 3}. The results of these studies showed that this kind of ferritic stainless steel would be more suitable to be used as anodic supports where a rich hydrogen atmosphere is employed. Preliminary deposition tests allowed obtaining a homogeneous Ni–YSZ anode layer with a thickness of 10 μm on the porous metallic substrates. - Highlights: • 430L stainless steel porous supports were obtained by powder extrusion moulding. • Porosity degree was controlled sintering at different temperatures in low vacuum. • Tensile tests allowed determining mechanical strength of porous supports. • A study about its oxidation behaviour in static air at high temperature was realized. • After oxidation, formed oxides were characterized by EDS–SEM and XRD.

36 MATERIALS SCIENCE↗

DOE OSTI2014

Microstructure and mechanical properties of bulk highly faulted fcc/hcp nanostructured cobalt microstructures

Nanostructured cobalt powders with an average particle size of 50 nm were synthesized using a polyol method and subsequently consolidated by spark plasma sintering (SPS). SPS experiments performed at 650 °C with sintering times ranging from 5 to 45 min under a pressure of 100 MPa, yielded to dense bulk nanostructured cobalt (relative density greater than 97%). X-ray diffraction patterns of the as-prepared powders showed only a face centered cubic (fcc) crystalline phase, whereas the consolidated samples exhibited a mixture of both fcc and hexagonal close packed (hcp) phases. Transmission electron microscopy observations revealed a lamellar substructure with a high density of nanotwins and stacking faults in every grain of the sintered samples. Room temperature compression tests, carried out at a strain rate of 10{sup −3} s{sup −1}, yielded to highest strain to fracture values of up to 5% for sample of holding time of 15 min, which exhibited a yield strength of 1440 MPa, an ultimate strength as high as 1740 MPa and a Young's modulus of 205 GPa. The modulus of elasticity obtained from the nanoindentation tests, ranges from 181 to 218 GPa. The lowest modulus value of 181 GPa was obtained for the sample with the highest sintering time (45 min), which could be related to mass density loss as a consequence of trapped gases releasing. - Highlights: • Co nanopowder (50 nm) was prepared by reduction in polyol medium. • SPS was used to process bulk nanostructured Co specimens. • Microstructures were made of intricate fcc/hcp, along with nanotwins and SFs. • High strengths and moderate compressive ductility were obtained. • Deformation mechanisms related to complex interplay of different length scales.

36 MATERIALS SCIENCE↗

DOE OSTI2014

Mechanically induced self-propagating reaction and consequent consolidation for the production of fully dense nanocrystalline Ti{sub 55}C{sub 45} bulk material

We employed a high-energy ball mill for the synthesis of nanograined Ti{sub 55}C{sub 45} powders starting from elemental Ti and C powders. The mechanically induced self-propagating reaction that occurred between the reactant materials was monitored via a gas atmosphere gas-temperature-monitoring system. A single phase of NaCl-type TiC was obtained after 5 h of ball milling. To decrease the powder and grain sizes, the material was subjected to further ball milling time. The powders obtained after 200 h of milling possessed spherical-like morphology with average particle and grain sizes of 45 μm and 4.2 nm, respectively. The end-products obtained after 200 h of ball milling time, were then consolidated into full dense compacts, using hot pressing and spark plasma sintering at 1500 and 34.5 MPa, with heating rates of 20 °C/min and 500 °C/min, respectively. Whereas hot pressing of the powders led to severe grain growth (∼ 436 nm in diameter), the as-spark plasma sintered powders maintained their nanograined characteristics (∼ 28 nm in diameter). The as-synthesized and as-consolidated powders were characterized, using X-ray diffraction, high-resolution electron microscopy, and scanning electron microscopy. The mechanical properties of the consolidated samples obtained via the hot pressing and spark plasma sintering techniques were characterized, using Vickers microhardness and non-destructive testing techniques. The Vickers hardness, Young's modulus, shear modulus and fracture toughness of as-spark plasma sintered samples were 32 GPa, 358 GPa, 151 GPa and 6.4 MPa·m{sup 1/2}, respectively. The effects of the consolidation approach on the grain size and mechanical properties were investigated and are discussed. - Highlights: • Room-temperature synthesizing of NaCl-type TiC • Dependence on the grain size on the ball milling time • Fabrication of equiaxed nanocrystalline grains with a diameter of 4.2 nm • Fabrication of nanocrystalline bulk TiC material by SPS with minimal grain growth • Dependence of improved mechanical properties on the consolidation techniques.

36 MATERIALS SCIENCE↗

DOE OSTI2018

The facile synthesis, crystallization behavior and magnetic property of FeNiP amorphous nanoparticles

Highlights: • A facile chemistry method was proposed to synthesize amorphous FeNiP nanoparticle. • Phase transformation happened during sintering the amorphous nanoparticle. • Ni nanospheres and monoclinic (Ni,Fe){sub 3}[PO4]{sub 2} nanorods appeared at 800 °C. • Crystallization behavior is α-FeNiP → Ni + FeNi{sub 3} + Ni{sub 3}P → Ni + (Ni,Fe){sub 3}[PO{sub 4}]{sub 2}. • Sintered powders have varied magnetic properties due to phase proportion change. - Abstract: Amorphous FeNiP nanoparticles with homogeneous composition are synthesized by reduction of aqueous Fe{sup 2 +} and Ni{sup 2 +} with sodium borohydride (NaBH{sub 4}) and hypophosphite at room temperature. These amorphous nanoparticles can be crystallized by heating up to 300 °C to form FeNi{sub 3} and Ni{sub 3}P crystals. Ni phase appeared at the sintering temperature of 500 °C, and a special net structure was formed at 700 °C due to the joining and diffusion among different nanoparticles. At a higher temperature of 800 °C, phase transformation happened and only pure Ni nanospheres and monoclinic ((Ni, Fe){sub 3}[PO{sub 4}]{sub 2}) nanorods can be observed, which should be governed by the long-range diffusion in the net structure. The amorphous FeNiP nanoparticles have excellent soft magnetic property with Ms of 13.2 emu/g and Hc of 0.7 Oe. However, the sintered mixing nanoparticles show varied magnetic properties due to the phase transformation and proportion change among different phases involved in.

77 NANOSCIENCE AND NANOTECHNOLOGY↗

DOE OSTI2018

Comparative investigation on microstructures and mechanical properties of (TiB + TiC)/Ti-6Al-4V composites from Ti-B4C-C and Ti-TiB2-TiC systems

Highlights: • The (TiB{sub w}+TiC{sub p})/Ti-6Al-4V composites were fabricated from Ti-B{sub 4}C-C and Ti-TiB{sub 2}-TiC systems by reactive hot-pressed sintering. • Microstructures and mechanical properties of the two kinds of composites were comparatively investigated. • The composites from Ti-TiB{sub 2}-TiC system possess higher elastic modulus and Vickers hardness than those from Ti-B{sub 4}C-C system. • The composites from Ti-TiB{sub 2}-TiC system have higher bending strength than the other system while employing same conditions. • The composites from Ti-B{sub 4}C-C system present better abrasion resistance than those from Ti-TiB{sub 2}-TiC system. - Abstract: Two percentages of TiB + TiC reinforced Ti-6Al-4V composites from Ti-B{sub 4}C-C and Ti-TiB{sub 2}-TiC systems were fabricated by reactive hot-pressed sintering. Their microstructures and mechanical properties involving elastic modulus, Vickers hardness, bending strength and wear property were investigated comparatively. The experimental results show that needle-like TiB whiskers and near-equiaxed TiC particles are evenly distributed in the Ti-6Al-4V matrix. The mechanical properties of the (TiB + TiC)/Ti-6Al-4V composites are closely related with the nominal composition and synthesis system of TiB + TiC reinforcement and the microstructures of composites. With increasing the nominal volume fraction of reinforcement, both elastic modulus and Vickers hardness increase more or less and the bending strength decreases in varying degrees. A certain increase of pores in the composites with the sintering temperature increasing to 1300 °C can markedly affect the bending strength. Moreover, no matter what the sintering temperature and nominal volume fraction of reinforcement, the elastic modulus and Vickers hardness of composites from the Ti-TiB{sub 2}-TiC system are higher than those from the Ti-B{sub 4}C-C system. Similarly, the composites from the Ti-B{sub 4}C-C system present better abrasion resistance than those from the Ti-TiB{sub 2}-TiC system due to the difference of interfacial bonding between the TiC particles and Ti-6Al-4V matrix in the two kinds of composites.

36 MATERIALS SCIENCE↗

DOE OSTI2013

Magneto acoustical emission in nanocrystalline Mn–Zn ferrites

Graphical abstract: Mn{sub 0.4}Zn{sub 0.6}Fe{sub 2}O{sub 4} powders were prepared by microwave hydrothermal method. The powders were characterized by X-ray diffraction, transmission electron microscope. The powders were sintered at different temperatures 400, 500, 600, 700, 800 and 900 °C/30 min using microwave sintering method. The grain size was estimated by scanning electron microscope. The room temperature dielectric and magnetic properties were studied in the frequency range (100 kHz–1.8 GHz). The magnetization properties were measured upto 1.5 T. The acoustic emission has been measured along the hysteresis loops from 80 K to Curie temperature. It is found that the magneto-acoustic emission (MAE) activity along hysteresis loop is proportional to the hysteresis losses during the same loop. This law has been verified on series of polycrystalline ferrites and found that the law is valid whatever the composition, the grain size and temperature. It is also found that the domain wall creation/or annihilation processes are the origin of the MAE. - Highlights: • The AE been measured along the hysteresis loops from 80 K to Curie temperature. • The MAE activity along hysteresis loop is proportional to P{sub h} during the same loop. • It is found that the domain wall creation/or annihilation processes are the origin of the MAE. - Abstract: Mn{sub 0.4}Zn{sub 0.6}Fe{sub 2}O{sub 4} powders were prepared by microwave hydrothermal method. The powders were characterized by X-ray diffraction, transmission electron microscope. The powders were sintered at different temperatures 400, 500, 600, 700, 800 and 900 °C/30 min using microwave sintering method. The grain size was estimated by scanning electron microscope. The room temperature dielectric and magnetic properties were studied in the frequency range (100 kHz–1.8 GHz). The magnetization properties were measured upto 1.5 T. The acoustic emission has been measured along the hysteresis loops from 80 K to Curie temperature. It is found that the magneto-acoustic emission (MAE) activity along hysteresis loop is proportional to the hysteresis losses during the same loop. This law has been verified on series of polycrystalline ferrites and found that the law is valid whatever the composition, the grain size and temperature. It is also found that the domain wall creation/or annihilation processes are the origin of the MAE.

36 MATERIALS SCIENCE↗

DOE OSTI2014

A new glass-free LTCC microwave ceramic – (1 − x) Li{sub 2.08}TiO{sub 3} + xLiF

Graphical abstract: - Highlights: • Sintering temperature of Li{sub 2}TiO{sub 3} was reduced to 900 °C by doping with LiF and excessive lithium. • A new glass-free LTCC microwave ceramic – (1 − x) Li{sub 2.08}TiO{sub 3} + xLiF was obtained. • The obtained LTCC material exhibited excellent microwave dielectric properties. - Abstract: The structure and microstructure of the (1 − x) Li{sub 2.08}TiO{sub 3} + xLiF (0.11 ≤ x ≤ 0.14) ceramics were studied by X-ray powder diffraction (XRD), thermal dilatometry and scanning electron microscopy (SEM). The microwave dielectric properties of the ceramics were studied with a network analyzer. All samples exhibited single monoclinic phase. The sintering temperature was successfully reduced to about 900 °C/2 h for the LiF-doped Li{sub 2.08}TiO{sub 3} specimens. The dielectric permittivity slightly decreased, whereas the Q × f value changed little, with the increase in LiF dopant. The temperature coefficient of resonant of frequency (τ{sub f}) value changed from positive to negative with increasing x, and a near zero value was obtained at x = 0.13 composition. Optimized microwave dielectric properties with ε{sub r} = ∼22.8, Q × f = ∼63,000 GHz and τ{sub f} = ∼1.0 ppm/°C for x = 0.13 composition sintered at 900 °C/2 h. The XRD and back scattering SEM analysis showed that the ceramic was compatible with Ag powders after sintering at 900 °C/2 h.

36 MATERIALS SCIENCE↗

DOE OSTI2018

Braunite phase embedded Y2O3/MnO2-Al2O3-CaO-SiO2 glass ceramics and their properties

Highlights: • Nucleation of synthetic braunite structure (Mn{sub 7}SiO{sub 12}) on sintering of Y{sub 2}O{sub 3}/MnO{sub 2}-CaO-Al{sub 2}O{sub 3}-SiO{sub 2} glasses at 850 °C. • Lossy capacitor behaviour. • Exhibits a critical temperature in 500–600 °C range. • Conduction mechanism shift from Superlinear power law to universal dielectric response law with increase in temperature. - Abstract: Glass series (20-x)Y{sub 2}O{sub 3}-xMnO{sub 2}-20Al{sub 2}O{sub 3}-40SiO{sub 2}-20CaO (x = 5, 10, 15 and 20, mol%) have been synthesized by melt quench technique followed by sintering at 850 °C. The optical band gap of the samples is in wide semiconductor range and increased with MnO{sub 2} content. Photoluminescence study exhibits emission in Mn{sup 2+} d-states. On the other hand, hardness decreases with MnO{sub 2} content except for 10 mol% MnO{sub 2} containing glasses (YM10). The formation of braunite phase in glass ceramics induces capacitive losses. In lower temperature region, the conductivity behaviour of samples follows superlinear power law. In higher temperature region, it follows the universal law of conduction. The dielectric constant for the sintered glasses is constant with respect to temperature, approximately upto 350 °C and 1 MHz frequency. Above 350 °C, the ionic conduction dominates in all the sintered glasses. The anomaly in properties is observed when the ratio of Y{sub 2}O{sub 3}/MnO{sub 2} is 1:1.

75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND↗

DOE OSTI2018

Superconductor-in-an-Hour: Spark Plasma Synthesis of Co- and Ni-Doped BaFe 2 As 2

In this work, BaFe 2 As 2 superconductors doped with Co or Ni were synthesized by heat treatment of the reactive BaH 2 precursor and elemental Fe, Co, Ni, and As in a sealed niobium container. The hydride route provides better mixing of the starting materials, resulting in faster preparation of the target phases. The hydrogen gas evolved during sintering facilitates the preparation of the oxygen-free powders. Using powder X-ray diffraction (PXRD), including low-temperature synchrotron PXRD, it was shown that this route leads to successful doping of the Co (Ni) dopant and that the actual dopant content in the produced powdered samples of BaFe 2– x Co x As 2 (0 ≤ x ≤ 0.4) and BaFe 2– x Ni x As 2 (0 ≤ x ≤ 0.18) is close to the nominal content. The optimally doped samples of BaFe 2– x Co x As 2 and BaFe 2– x Ni x As 2 exhibit bulk superconducting properties. The highest T c for the Co-doped sample is 24 K when x = 0.15–0.175 and 21 K for the Ni-doped sample when x ~ 0.1. The reaction mechanism between the BaH 2 hydride precursor and elemental Fe and As was studied by operando high-temperature synchrotron PXRD. The formation of the target BaFe 2 As 2 phase occurs at the relatively low temperature of 785 K with binary iron arsenide (FeAs) being an intermediate product. Finally, the in situ combined synthesis and sintering of the intimately mixed BaH 2 and Fe, Co, and As was performed inside the spark plasma sintering apparatus to obtain compact pellets of the BaFe 2– x Co x As 2 superconductors. A higher sintering temperature (>873 K) is needed to ensure a homogeneous Co dopant distribution and, thus, the abrupt superconducting transitions.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗

DOE OSTI2015

Low thermal budget photonic processing of highly conductive Cu interconnects based on CuO nanoinks. Potential for flexible printed electronics

The developing field of printed electronics nanoparticle based inks such as CuO show great promise as a low-cost alternative to other metal-based counterparts (e.g., silver). In particular, CuO inks significantly eliminate the issue of particle oxidation, before and during the sintering process, that is prevalent in Cu-based formulations. We report here the scalable and low-thermal budget photonic fabrication of Cu interconnects employing a roll-to-roll compatible pulse-thermal-processing (PTP) technique that enables phase reduction and subsequent sintering of inkjet-printed CuO patterns onto flexible polymer templates. Detailed investigations of curing and sintering conditions were performed to understand the impact of PTP system conditions on the electrical performance of the Cu patterns. Specifically, the impact of energy and power of photonic pulses on print conductivity was systematically studied by varying the following key processing parameters: pulse intensity, duration and sequence. Through optimization of such parameters, highly conductive prints in < 1 s with resistivity values as low as 100 n m has been achieved. We also observed that the introduction of an initial ink-drying step in ambient atmosphere, after the printing and before sintering, leads to significant improvements in mechanical integrity and electrical performance of the printed Cu patterns. Moreover, the viability of CuO reactive inks, coupled with the PTP technology and pre ink-drying protocols, has also been demonstrated for the additive integration of a low-cost Cu temperature sensor onto a flexible polymer substrate.

77 NANOSCIENCE AND NANOTECHNOLOGY↗

DOE OSTI2015

Study of La{sub 0.9}Sr{sub 0.1}MnO{sub 3} manganite at different temperature

In this paper, the effect of sintering temperature on the structural properties of Sr doped lanthanum manganites is studied. The Sr doped manganites are synthesized using solid state reaction method. The structural properties of the sintered powders are examined by X-ray diffraction. The La{sub 0.9}Sr{sub 0.1}MnO{sub 3} powder samples exhibit a dominant peak along with increased peak intensity corresponding to the (104), (202), (204) reflections and some new peaks also appeared along (116),(036) and (0210) reflections compared to first sintering temperature (1250°C). This confirms a more polycrystalline nature of the powder at higher sintering temperature. The crystallite size varies between 45 nm to 50 nm. For relative study, the calculated average crystallite size and lattice parameters are noted in tabulated form.

71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSIC↗

DOE OSTI2016

Effect of electrode material on characteristics of non-volatile resistive memory consisting of Ag{sub 2}S nanoparticles

In this study, Ag{sub 2}S nanoparticles are synthesized and used as the active material for two-terminal resistance switching memory devices. Sintered Ag{sub 2}S films are successfully crystallized on plastic substrates with synthesized Ag{sub 2}S nanoparticles, after a relatively low-temperature sintering process (200 °C). After the sintering process, the crystallite size is increased from 6.8 nm to 80.3 nm. The high ratio of surface atoms to inner atoms of nanoparticles reduces the melting point temperature, deciding the sintering process temperature. In order to investigate the resistance switching characteristics, metal/Ag{sub 2}S/metal structures are fabricated and tested. The effect of the electrode material on the non-volatile resistive memory characteristics is studied. The bottom electrochemically inert materials, such as Au and Pt, were critical for maintaining stable memory characteristics. By using Au and Pt inert bottom electrodes, we are able to significantly improve the memory endurance and retention to more than 10{sup 3} cycles and 10{sup 4} sec, respectively.

77 NANOSCIENCE AND NANOTECHNOLOGY↗

DOE OSTI2019

Solid–state synthesis of multicomponent equiatomic rare–earth oxides

Phase formation in multicomponent rare–earth oxides is determined by a combination of composition, sintering atmosphere, and cooling rate. Polycrystalline ceramics comprising various combinations of Ce, Gd, La, Nd, Pr, Sm, and Y oxides in equiatomic proportions were synthesized using solid–state sintering. The effects of composition, sintering atmosphere, and cooling rate on phase formation were investigated. Single cubic or monoclinic structures were obtained with a slow cooling of 3.3°C/min, confirming that rare–earth oxides follow a different structure stabilization process than transition metal high–entropy oxides. In an oxidizing atmosphere, both Ce and Pr induce a cubic structure, while only Ce plays that role in an inert or reducing atmosphere. Samples without Ce or Pr develop a single monoclinic structure. The structures formed at initial synthesis may be converted to a different one, when the ceramics are annealed in an additional atmosphere. Phase evolution of a five–cation composition was also studied as a function of sintering temperature. In conclusion, the binary oxides used as raw materials completely dissolve into a single cubic structure at 1450°C in air.

36 MATERIALS SCIENCE↗

DOE OSTI2026

Novel additive manufacturing for plasma facing materials ‐ creating a research pathway for minority students

This project addresses two critical and intertwined challenges in fusion energy, namely the shortage of a broadly trained scientific workforce and the lack of scalable manufacturing solutions for plasma-facing components (PFCs). Through a collaboration among Florida International University (FIU), Miami Dade College (MDC), and Purdue University, the project established structured, reproducible educational and research pathways that recruit and advance students from institutions historically outside the fusion energy enterprise, building the human capital that this field urgently needs. The project integrates the complementary research strengths of FIU and Purdue to investigate flash sintering as a transformative processing route for tungsten-based PFCs. Unlike conventional sintering approaches, flash sintering offers rapid densification at significantly reduced thermal budgets, making it a compelling candidate for fabricating complex tungsten geometries that must withstand extreme plasma-facing environments. Systematic experimental and modeling efforts will elucidate the fundamental mechanisms governing microstructure evolution, grain boundary chemistry, and thermomechanical response during flash sintering — knowledge that is presently lacking but essential for translating this technology into reliable manufacturing practice. The convergence of workforce development and cutting-edge manufacturing research positions this project to deliver measurable, durable impact: a pipeline of fusion-ready researchers cultivated through expanded institutional partnerships, and a validated materials processing framework that accelerates domestic readiness for next-generation fusion reactor construction.

70 PLASMA PHYSICS AND FUSION TECHNOLOGY↗

NASA NTRSDate not supplied

Scaleup of Microwave Powder Bed Fusion for Lunar Infrastructure Construction

NASA and its partners are seeking to establish a sustainable and permanent presence on the Moon. Like explorers on Earth, making use of natural resources upon arrival at the destination will be paramount. In-situ resource utilization of the lunar regolith will enable efficient construction of lunar infrastructure. Transforming the granular regolith into a solid can be achieved in many ways. One method is to use microwave energy to sinter the regolith into various structures. The lunar regolith has a low thermal conductivity, but microwaves can volumetrically heat it to bind the granular particles together in an energy efficient manner. One concept that is being developed and evaluated to sinter the regolith into infrastructure uses the Moon’s surface as a powder bed. Regolith would be added to the sintered lunar structure to build up layers to create structures such as landing pads, blast shields, roads, etc. Microwave systems, concept of operations, and sintering protocols are being developed to create a sub-element structure targeted for a lunar demonstration mission.

microwave↗

DOE OSTI2024

CEFAS Poster for Advanced Manufacturing Workshop 3/26/24

Electric-field assisted sintering (EFAS) is an advanced manufacturing method for the consolidation and processing of ceramic and metal materials. It is a particularly excellent candidate for efficient materials processing as it has greater than 90% energy cost savings and improved CO2 emissions compared to traditional sintering in a furnace. This is due to direct rapid heating of the materials and molds leveraging an electrification phenomenon called Joule heating where electrical current is passed through the sample/mold assemblies causing direct heating. The technique does have limitations though as it is traditionally a batch-process and suffers from scale up difficulties. To overcome this, researchers at Idaho National Laboratory changed the form factor of traditional EFAS instruments to develop and construct a continuous rolling electric-field assisted sintering (CEFAS) device.

36 MATERIALS SCIENCE↗