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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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At least 901 records · Page 50
All sourcesNASA NTRSDOE OSTI
NASA NTRS2008

The Characterization of the Selected Materials for Space Shuttle

The harsh conditions to which the Space Shuttles are exposed during flight required the development and use of many unique materials. These materials were specially designed to withstand extreme temperatures, in some cases over 1600 C, while other material must withstand the cryogenic conditions of -253 C, and others must operate while under extreme loads. All of these materials must not only operate in the harsh condition but they must be light weight as well. The Space Shuttle is composed of three major components when configured for launch, Figure 1; the Shuttle, solid rocket boosters, and external tank (ET). The different heat shields of the Shuttle make up the thermal protection system (TPS); this system consists of many different types of components designed to operate on various parts of the vehicle. The body of the Shuttle and ET are composed mainly of aluminum alloy and graphite epoxy. The TPS consists of reinforced carbon-carbon (RCC) used on the wing leading edges and nose cap areas while the upper forward fuselage areas, the entire underside of the Shuttle, the Orbiter maneuvering system, and reaction control system utilize blacc high temperature reusable surface insulation (HRSI) tiles, Figure 2. Other areas of the Orbiter are protected by fibrous refractory composite insulation (FRCI) tiles. Areas where the temperature stays below 649 C, such as the forward fuselage, mid-fuselage, aft fuselage, vertical tail, and upper wing, are protected by other material such as, white low temperature reusable surface insulation (LRSI) tiles, advanced flexible reusable surface insulation (AFRSI) blankets, and felt reusable surface insulation (FRSI) white blankets. The RCC is a pyrolized laminated carbon with the outer surface converted to silicon carbide to prevent oxidation. The FiRST tiles are made of a low-density, high purity silica 99.8-percent amorphous fiber insulation that is made rigid by ceramic bonding resulting in 90-percent void and 10-percent materials. The RCC and HRSI are used in areas where the temperature rises above 1260 T. The FRCI tiles are high strength tiles derived by adding alumina-bososilicate fiber to the pure silica tile slurry that welds the micron-sizes fibers of pure silica into a rigid structure during sintering. The FRCI is composed of 20-percent alumina-borosilicate fibers and 80-percent silica fibers, and provided improved strength, durability and resistance to coating cracking and weight reduction than HRSI.

Kim, Hae-Soo↗
NASA NTRS2016

Additively Manufactured Low Cost Upper Stage Combustion Chamber

Over the past two years NASA's Low Cost Upper Stage Propulsion (LCUSP) project has developed Additive Manufacturing (AM) technologies and design tools aimed at reducing the costs and manufacturing time of regeneratively cooled rocket engine components. High pressure/high temperature combustion chambers and nozzles must be regeneratively cooled to survive their operating environment, causing their design fabrication to be costly and time consuming due to the number of individual steps and different processes required. Under LCUSP, AM technologies in Sintered Laser Melting (SLM) GRCop-84 and Electron Beam Freeform Fabrication (EBF3) Inconel 625 have been significantly advanced, allowing the team to successfully fabricate a 25k-class regenerative chamber. Estimates of the costs and schedule of future builds indicate cost reductions and significant schedule reductions will be enabled by this technology. Characterization of the microstructural and mechanical properties of the SLM-produced GRCop-84, EBF3 Inconel 625 and the interface layer between the two has been performed and indicates the properties will meet the design requirements. The LCUSP chamber is to be tested with a previously demonstrated SLM injector in order to advance the Technology Readiness Level (TRL) and demonstrate the capability of the application of these processes. NASA is advancing these technologies to reduce cost and schedule for future engine applications and commercial needs.

Protz, Christopher↗
NASA NTRS1993

Advances in Studies of Electrode Kinetics and Mass Transport in AMTEC Cells

Previous work reported from JPL has included characterization of electrode kinetics and alkali atom transport from electrodes including Mo, W, WRh x (Mn), in sodium AMTEC cells and vapor exposure cells; and Mo in potassium vapor exposure cells. These studies were generally performed in cells with small area electrodes (about 1 to 5 cm 2 ), and device geometry had little effect on transport. Alkali metal diffusion coefficients through these electrodes have been characterized, and approximate surface diffusion coefficients were derived in cases of activated transport. A basic model of electrode kinetics and transport at the alkali metal vapor/pourous metal electrode/alkali beta"-alumina solid electrolyte (BASE) three phase boundary has been proposed which accounts for electrochemical reaction rates with a collision frequency near the three phase boundary and tunneling from the porous electrode partially covered with adsorbed alkali metal atoms. The small electrode effect in AMTEC cells has been discussed in several papers, but quantitative investigations have described only the overall effect and the important contribution of electrolyte resistance. The quantitative characterization of transport losses in cells with large area electrodes has been limited to simulations of large area electrode effects, or characterization of transport losses from large area electrodes with significant longitudinal temperature gradients. This paper describes new investigations of electrochemical kinetics and transport, with four 14.4 cm 2 WPt 3.5 electrodes, including the influence of electrode size on the mass transport loss in the AMTEC cell. These electrodes exhibit very slow sintering, as well as excellent sodium transport properties, making them attractive candidates for AMTEC power conversion use. However, the facile sodium transport in WPt 3.5 electrodes makes characterization of the transport process difficult.

electrode↗
DOE OSTI2023

A Comparative Radiative Property Evaluation of Sintered Bauxite and AMS4003 Ceramic Particles

The radiative properties of sintered bauxite (ACCUCAST ID80) and AMS4003 particles were measured and compared to assess their performances as direct absorption and heat transfer media for particle-based concentrated solar power (CSP) plants. Reflectance measurements were performed over the spectral range 0.2–20 µm and used to calculate solar and thermal emission properties of the particles. In addition, reflectance was measured as a function of temperature up to 1000 °C for the spectral range 1–20 µm. The solar absorptance of AMS4003 was greater than that of ACCUCAST both before and after thermal cycling of the materials at 1000 °C, although thermal cycling was found to substantially decrease the solar absorptance of both materials. The thermal emittance of AMS4003 was also greater than that of ACCUCAST at all temperatures tested. Finally, the radiaitve properties measured in this study were used to estimate absorber efficiencies as a way to compare the particles in terms of their performance in a solar receiver. AMS4003 yielded greater efficiencies than ACCUCAST, suggesting its potential as a material for CSP.

14 SOLAR ENERGY↗
NASA NTRSDate not supplied

Characterizing the Effects of Thermal Profile and Gas Environment on the Heat Treatment of JSC-1A Lunar Simulant Using Combined Thermogravimetry and Mass Spectroscopy

As NASA strives towards a long duration presence on the Moon, it has become increasingly important to learn how to better utilize resources from the lunar surface for everything from habitats, vehicle infrastructure, and chemical extraction. To that end, a variety of lunar simulants have been sourced from terrestrially available volcanic minerals and glass as Apollo regolith is a finite resource unavailable for experimentation needing large masses. However, while mineralogy and chemical composition can approach that of lunar material in these simulants, there are still distinct non-lunar phases such as hydrates, carbonates, sulfates, and clays that can cause simulants to behave distinctly non-lunar in a variety of processing conditions that would ideally be applied to lunar material. Notably, severe glassy bubbling has been documented in a variety of vacuum sintering experiments on JSC-1A lunar Maria simulant heated via microwaves. The origins of this outgassing have not been well understood, but are normally attributed to the decomposition of non-lunar contaminates intrinsic to virtually all terrestrially sourced simulants. As such, a series of controlled environmental tests were performed to ascertain the origins of the high temperature outgassing and to develop heat treatments that can drive JSC-1A closer to lunar composition and behavior. It was found that in JSC-1A that distinct gas evolutions of water, carbon dioxide, and sulfur dioxide occur in both inert gas and vacuum. Additionally, the presence of hydrogen during heat treatments was shown to dramatically change gas evolutions, leading to distinctly more lunar-like composition and behavior from JSC-1A simulant.

sinter↗
NASA NTRSDate not supplied

Characterizing the Effects of Thermal Profile and Gas Environment on the Heat Treatment of JSC-1A Lunar Simulant Using Combined Thermogravimetry and Mass Spectroscopy

As NASA strives towards a long duration presence on the Moon, it has become increasingly important to learn how to better utilize resources from the lunar surface for everything from habitats, vehicle infrastructure, and chemical extraction. To that end, a variety of lunar simulants have been sourced from terrestrially available volcanic minerals and glass as Apollo regolith is a finite resource unavailable for experimentation needing large masses. However, while mineralogy and chemical composition can approach that of lunar material in these simulants, there are still distinct non-lunar phases such as hydrates, carbonates, sulfates, and clays that can cause simulants to behave distinctly non-lunar in a variety of processing conditions that would ideally be applied to lunar material. Notably, severe glassy bubbling has been documented in a variety of vacuum sintering experiments on JSC-1A lunar Maria simulant heated via microwaves. The origins of this outgassing have not been well understood, but are normally attributed to the decomposition of non-lunar contaminates intrinsic to virtually all terrestrially sourced simulants. As such, a series of controlled environmental tests were performed to ascertain the origins of the high temperature outgassing and to develop heat treatments that can drive JSC-1A closer to lunar composition and behavior. It was found that in JSC-1A that distinct gas evolutions of water, carbon dioxide, and sulfur dioxide occur in both inert gas and vacuum. Additionally, the presence of hydrogen during heat treatments was shown to dramatically change gas evolutions, leading to distinctly more lunar-like composition and behavior from JSC-1A simulant.

sinter↗
DOE OSTI2022

Experimental validation of multiphysics model simulations of the thermal response of a cement clinker rotary kiln at laboratory scale

Abstract An increasing demand for buildings, transportation systems and civil infrastructure development has driven expansion of cement consumption world‐wide, producing a significant increase in related global energy demand. With approximately 7% of the world‐wide industrial energy consumption (10.7 exajoules [EJ]), the cement industry is the third most energy intensive industrial processes and a key component for concrete, the most consumed composite material in the global construction industry. In cement manufacturing, the cement kiln accounts for most of the energy consumption in the production process. As the heart of a cement plant, the cement kiln is where the kiln feed primarily containing calcium oxide (CaO), silica (SiO 2 ), alumina (Al 2 O 3 ), and iron (Fe 2 O 3 ) are thermally and chemically transformed into clinker minerals. The presented work developed a multiphysics model, designed and built a laboratory‐scale rotary cement clinker kiln, and produced cement clinker at laboratory‐scale. The model was developed to study the interaction between the various thermal, fluid dynamic and chemical interactions involved in the sintering process used to form Portland cement clinker in an effort to reduce energy use. The analytical model was validated through experimental testing using a unique laboratory‐scale rotary cement kiln developed during the investigation. Also demonstrated was the feasibility of producing clinker at laboratory scale. This modeling and lab scale tests were designed to better understand the clinker sintering process so that operational and quality decisions can be made to optimize energy consumption without compromising cement clinker quality. The computational fluid dynamics modeling was developed in COMSOL Multiphysics 6.0. The characteristics of the combustion fluid flow, concentration of species, temperature and heat transfer were studied for a turbulent flow of methane (CH 4 ) gas and oxygen (O 2 ). Theory suggests that heat transfer impacts the cement production process but the multiphysics model more accurately describes the convection, conduction, and radiant heat transfer in the kilning process and thus allows for a better understanding of the energy exchange driving the chemical reactions that produce Portland cement. Clinker minerals were formed because of appropriate burning conditions implemented during experimental model validation.

Tabares, Juan David↗
DOE OSTI2022

Liquid lithium wetting and percolation in a porous tungsten/liquid Li plasma facing component (PFC)

This work explores the concept of a hybrid material system designed to protect the plasma from high-Z material emission while also protecting an underlying high-Z wall material from erosion by integrating a low-Z component in the liquid phase. Plasma-surface interaction properties of a porous tungsten (W)-liquid metal hybrid system, having the favorable bulk thermomechanical properties of W while serving as a scaffold for a liquid metal with self-healing and radiative vapor shielding characteristics, are examined. W-substrates with 70% density of bulk W and 1–5 μm sized pores have been fabricated with 50-nm W powders using spark plasma sintering. Enhanced lithium (Li) wettability, driven by percolation through the porous W architecture, is demonstrated with in-situ liquid Li drop measurements. Finally, results show complete wetting of liquid Li at 250 °C in the porous W, 100 °C lower temperature than what has been observed on traditional W surfaces. In operando ion beam analysis of Li films deposited on porous W substrates provides microscopic evidence of Li percolation into the substrate and a first look at D retention up to a depth of 100 nm after plasma exposure at a flux of 10 20 m –2 s –1 , 250 eV/amu D + plasma to a fluence of 1.16 × 10 23 m –2 at a temperature of 200 °C.

70 PLASMA PHYSICS AND FUSION TECHNOLOGY↗
DOE OSTI2020

Hydrothermal reactivity of neutron absorber composites

The stability of neutron absorber composite materials at hydrothermal conditions was tested in a series of two-week experiments to mimic spent nuclear fuel disposal. Coupons, composed of boron carbide (B 4 C) sintered with and encased in aluminum, were increasingly altered in experiments at 150, 230, and 300 °C and pressures of 150 bar. Alteration of aluminum to boehmite (γ-AlO(OH)) and hydrogen gas generation occurred over the range of investigated temperatures, but is most significant at 300 °C. We found that the formation of boron-bearing mineral phases was not detected; however, aqueous boron was present in the reaction fluids.

36 MATERIALS SCIENCE↗
NASA NTRS1972

Non-gassing nickel-cadmium battery electrodes and cells

The concept of a negative limited nongassing nickel-cadmium battery was demonstrated by constructing and testing practical size experimental cells of approximately 25 Ah capacity. These batteries operated in a gas-free manner and had measured energy densities of 10-11 Wh/lb. Thirty cells were constructed for extensive testing. Some small cells were tested for over 200 cycles at 100% depth. For example, a small cell with an electrodeposited cadmium active mass on a silver screen still had 55% of its theoretical capacity (initial efficiency was 85%). There was no evidence of deterioration of gassing properties with cycling of the nickel electrodes. The charge temperature was observed to be the most critical variable governing nickel electrode gassing. This variable was shown to be age dependent. Four types of cadmium electrodes were tested: an electrodeposited cadmium active mass on a cadmium or silver substrate, a porous sintered silver substrate based electrode, and a Teflon bonded pressed cadmium electrode. The electrodeposited cadmium mass on a silver screen was found to be the best all-around electrode from a performance point of view and from the point of view of manufacturing them in a size required for a 25 Ah size battery.

Luksha, E.↗
NASA NTRS1978

High Velocity Burner Rig Oxidation and Thermal Fatigue Behavior of Si3N4- and SiC Base Ceramics to 1370 Deg C

One SiC material and three Si3N4 materials including hot-pressed Si3N4 as a baseline were exposed in a Mach-1-gas-velocity burner rig simulating a turbine engine environment. Criteria for the materials selection were: potential for gas-turbine usage, near-net-shape fabricability and commercial/domestic availability. Cyclic exposures of test vanes up to 250 cycles (50 hr at temperature) were at leading-edge temperatures to 1370 C. Materials and batches were compared as to weight change, surface change, fluorescent penetrant inspection, and thermal fatigue behavior. Hot-pressed Si3N4 survived the test to 1370 C with slight weight losses. Two types of reaction-sintered Si3N4 displayed high weight gains and considerable weight-change variability, with one material exhibiting superior thermal fatigue behavior. A siliconized SiC showed slight weight gains, but considerable batch variability in thermal fatigue.

Sanders, W. A.↗
DOE OSTI2020

Filter 'Cook-Off': Filter Selection via Side-by-Side Testing at Actual Process Conditions - 20040

In 2005, the THOR steam reforming fluidized-bed reactor technology was selected by the U.S. Department of Energy for treatment of sodium-bearing waste at the INL. During the final phase of commissioning prior to radiological operations, regeneration of the high temperature filters in the process gas filter (PGF) vessel became ineffective. After approximately 50 days of testing, the differential pressure across the filters began increasing exponentially and the plant had to be shutdown. Subsequent investigation revealed that the Inconel 625 (I625) sintered metal filter media was corroding in the 550 deg. C reducing environment. A pilot plant run tested four candidate replacement filter media. The top candidate was further tested during a long-term pilot plant run to validate the selection. Data from the testing indicate the selected filters will provide reliable service throughout the life of the project, including after in-situ radiological decontamination. This paper presents the data from this effort and reinforces the value of pilot plant testing. (authors)

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗
NASA NTRS1986

Friction and wear of sintered Alpha SiC sliding against IN-718 alloy at 25 to 800 C in atmospheric air at ambient pressure

The sliding friction and wear of the SiC-nickel based alloy IN-718 couple under line contact test conditions in atmospheric air at a linear velocity of 0.18 m/sec and a load of 6.8 kg (67N) was investigated at temperatures of 25 to 800 C. It was found that the coefficient of friction was 0.6 up to 350 C then decreased to 0.3 at 500 and 800 C. It is suggested that the sharp decrease in the friction in the range of 350 to 550 C is due to the lubrication value of oxidation products. The wear rate reaches a minimum of 1 x 10 to the -10 to 2 x 10 to the -10 cu cm/cm/kg at 400 to 600 C.

Deadmore, Daniel L.↗
DOE OSTI2023

Densification and Immobilization of AgI-Containing Iodine Waste Forms Using Spark Plasma Sintering

Here in this study, porous Ag-xerogel (Ag-Xero), Ag-faujasite (Ag-FAU) zeolite, and Ag-mordenite (Ag-MOR) zeolite sorbents were loaded with iodine gas [I 2 (g)] under saturated conditions at 150 °C for 24 h, followed by densification and consolidation into monolithic waste forms using spark plasma sintering (SPS). For Ag-Xero materials, SPS pellets were made with as-loaded samples, while others were made with preheated (PH; 500 °C for 2 h) samples to help with densification. SPS processing was conducted at 50 MPa under different temperatures (T = 200–800 °C) for different times (t = 0.5–30 min), where eleven AgI-Xero samples, five AgI-FAU, and two AgI-MOR separate samples were produced. The primary goal was to look for the optimum processing parameters for each material to yield pellets with high iodine retentions, high densities, and low porosities while preventing AgI decomposition. The Ag-Xero showed the highest iodine loadings (qe = 470 mg g –1 ) compared to Ag-FAU (qe = 368 mg g –1 ) and Ag-MOR (qe = 108 mg g –1 ). Measured iodine concentrations were the highest in AgI-Xero pellets without PH, followed by AgI-Xero with PH, AgI-FAU, and then AgI-MOR. Silver utilization (I/Ag on a mol % basis) values were in the order of AgI-MOR ≈ AgI-Xero (no PH) > AgI-Xero (PH) > AgI-FAU. Chemical durabilities of SPS-densified AgI-Xero (PH) pellets were very favorable, with lower releases than SPS pellets made from AgI-Xero samples without PH. These results show promise for iodine waste form production.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
NASA NTRSDate not supplied

Laser Sintering of RTM385-SLS Thermoset Polyimides With Boron Nitride

RTM385-SLS is a melt-processable thermoset polyimide resin specially formulated with a complex melt viscosity (ƞ*) of ~104-105 poise for laser sintering. RTM385-SLS resin powder was mixed with 20-25% of hexagonal boron nitride (h-BN) and subjected to laser sintering (LS) to print out “Green” disks and dogbone specimens which could be further post-cured in an oven to complete the crosslinking of the reactive phenylethynyllphthalic anhydride (PEPA) terminal groups within the resin to achieve a very high glass transition temperature (T g ) of 385°C. The cured composite specimens were then subjected to thermal analysis, thermal conductivity measurement and mechanical testing for characterization.

Additive manufacturing↗
DOE OSTI2025

Microstructural Characteristics, Mechanical Properties, and Corrosion Behavior of Field-Assisted Diffusion Welded Alloy 617

This study investigated the microstructural characteristics, mechanical response, and corrosion resistance of Alloy 617 diffusion welded by electric field-assisted sintering (EFAS). The microstructure exhibited good grain boundary (GB) migration across the interface and flat interface in the samples bonded at different conditions. Graded grain size was observed, with grain coarsening being more significant near sample surface due to EFAS-induced temperature gradient. Tensile testing revealed that the specimens fractured in the matrix away from the interface. The peak strength of 807 MPa was obtained in the samples welded at 1000°C. The materials obtained at 1100°C exhibited reduced tensile strength but improved ductility. Strain maps revealed by digital image correlation showed the flat interfaces were less ductile compared to the matrix. The hardness reduced near sample surfaces due to enlarged grains induced by temperature gradient. The interfaces with GB migration exhibited improved corrosion resistance in molten salt compared to the flat interfaces.

36 - MATERIALS SCIENCE↗
NASA NTRSDate not supplied

Moon to Mars Planetary Autonomous Construction Technology (MMPACT) Lunar Surface Construction Activity at NASA Marshall Space Flight Center

Introduction: The goal of the Moon to Mars Planetary Autonomous Construction Technology (MMPACT) Project at NASA Marshall Space Flight Center (MSFC) is to develop, deliver, and demonstrate on-demand capabilities to protect astronauts and create infrastructure elements on the lunar surface via construction of landing pads, habitats, shelters, roadways, berms, and blast shields using lunar regolith-based materials. MSFC has strong collaborations with industry, academia, and other NASA Centers to accomplish this goal. The MMPACT project consists of three elements. The first focuses on the development of an autonomous construction system. The second focuses on construction feedstock materials development. The third element focuses on the development of a microwave sintering construction capability. The team plans to demonstrate construction on a small Commercial Lunar Payload Services (CLPS) lander in the 2025 timeframe, with a future goal of constructing a subscale landing pad in 2028-2029.The MMPACT project is funded through the Lunar Surface Innovation Initiative, which is part of the Space Technology Mission Directorate. Technology Development: The MMPACT team will evaluate multiple autonomous construction and microwave construction technologies, materials, and construction element forms. Selected technologies will be matured; processes and operations will be defined for the two flight missions. Evaluations of materials, as well as the technology itself, will be demonstrated in simulated lunar environments as part of the technology maturation process. The team is keenly aware of the properties of the lunar environment. Its temperature swings, negligible exosphere, and unprepared site foundations factor into the materials for both construction and hardware, the concept of operations, and the technology’s interdependencies. Materials: The team is looking at materials that can be produced from in-situ resources in an effort to make lunar construction cost-effective. The particular focus of the materials team is cementitious materials, metals, and sintered and melted regolith. These materials will be studied for tensile, compressive, and flexural strength. They will also be tested for their ability to handle thermal swings and vacuum. They will be fully characterized using various microscopy techniques to examine micro-structures, chemistry, and crystal formation. Interdependencies: There are many interdependencies that MMPACT has already identified. These include: •Excavation interface •Regolith feedstock beneficiation •Regolith feedstock storage and provision •Requirements for structures •Site-to-site mobility systems •Availability of lunar simulant •Lander off-loading capabilities •Navigation systems •Power •Regolith composition and mineralogy •Lander specifications •Communication protocols Technology developments in these additional areas would be beneficial to MMPACT.

Moon to Mars Planetary Autonomous Construction Tec↗
DOE OSTI2022

The influence of the processing parameters on the reactive flash sintering of ZrO 2 -CeO 2

Reactive flash sintering (RFS) is a method that was recently developed to produce dense single-phase bulk ceramic parts through solid-state reactions in a single-step that only takes a few minutes. The influence of the RFS parameters on the phase purity of a simple mixed oxide, (Zr 0.8 ,Ce 0.2 )O 2 , was investigated. Parameters such as furnace temperature, furnace atmosphere, electric current density, and alternating current (AC) or direct current (DC) were examined. It was found that (Zr 0.8 ,Ce 0.2 )O 2 pellets with high densities, above 90% of its theoretical density, can be produced by RFS in a few minutes when RFS occurs under oxidizing atmospheres, AC fields with current densities of 100 mA·mm –2 , and at a furnace temperature of 1200°C. Reducing conditions such as Ar-H 2 atmosphere and DC fields, low furnace temperatures, and low current densities resulted in phase impurities and poor reactions between the ZrO 2 and the CeO 2 powders. These results show that RFS is a useful method to produce mixed oxides, but it is very sensitive to the processing parameters. This is the first time that the influence of most of the RFS processing parameters has been studied systematically. Thus, the present work aims to provide guidelines on selecting the right processing parameters when exploring RFS.

36 MATERIALS SCIENCE↗