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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 55 records · Page 3
All sourcesNASA NTRSDOE OSTI
DOE OSTI2021

Acid-resistant catalyst supports and catalysts

A process for preparing a catalyst comprises coating substantial internal surfaces of porous inorganic powders with titanium oxide to form titanium oxide-coated inorganic powders. After the coating, an extrudate comprising the titanium oxide-coated inorganic powders is formed and calcined to form a catalyst support. Then, the catalyst support is impregnated with a solution containing one or more salts of metal selected from the group consisting of molybdenum, cobalt, and nickel.

Schmidt, Stephen R.↗
DOE OSTI2023

Acid-resistant catalyst supports and catalysts

A process for preparing a catalyst comprises coating substantial internal surfaces of porous inorganic powders with titanium oxide to form titanium oxide-coated inorganic powders. After the coating, an extrudate comprising the titanium oxide-coated inorganic powders is formed and calcined to form a catalyst support. Then, the catalyst support is impregnated with a solution containing one or more salts of metal selected from the group consisting of molybdenum, cobalt, and nickel.

Schmidt, Stephen R.↗
DOE OSTI2021

Out-of-equilibrium processes in crystallization of organic-inorganic perovskites during spin coating

Complex phenomena are prevalent during the formation of materials, which affect their processing-structure-function relationships. Thin films of methylammonium lead iodide (CH 3 NH 3 PbI 3 , MAPI) are processed by spin coating, antisolvent drop, and annealing of colloidal precursors. The structure and properties of transient and stable phases formed during the process are reported, and the mechanistic insights of the underlying transitions are revealed by combining in situ data from grazing-incidence wide-angle X-ray scattering and photoluminescence spectroscopy. Here, we report the detailed insights on the embryonic stages of organic-inorganic perovskite formation. The physicochemical evolution during the conversion proceeds in four steps: i) An instant nucleation of polydisperse MAPI nanocrystals on antisolvent drop, ii) the instantaneous partial conversion of metastable nanocrystals into orthorhombic solvent-complex by cluster coalescence, iii) the thermal decomposition (dissolution) of the stable solvent-complex into plumboiodide fragments upon evaporation of solvent from the complex and iv) the formation (recrystallization) of cubic MAPI crystals in thin film.

36 MATERIALS SCIENCE↗
NASA NTRS1979

Inorganic Zn2TiO4 thermal control coatings

Silicate-bonded zinc orthotitanate thermal control coatings for space applications have been developed. This paper discusses preparation of the pigment, paint formulation and application, and some properties of the coatings. Very high reflectance (low solar absorptance), high emittance, and good stability in an ultraviolet-vacuum environment are indicated for this paint.

Harada, Y.↗
NASA NTRS2002

A Systems Approach to the Solid Lubrication of Foil Air Bearings for Oil-Free Turbomachinery

Foil air bearings are self-acting hydrodynamic bearings which rely upon solid lubricants to reduce friction and minimize wear during sliding which occurs at start-up and shut-down when surface speeds are too low to allow the formation of a hydrodynamic air film. This solid lubrication is typically accomplished by coating the non-moving foil surface with a thin, soft polymeric film. The following paper introduces a systems approach in which the solid lubrication is provided by a combination of self lubricating shaft coatings coupled with various wear resistant and lubricating foil coatings. The use of multiple materials, each providing different functions is modeled after oil-lubricated hydrodynamic sleeve bearing technology which utilizes various coatings and surface treatments in conjunction with oil lubricants to achieve optimum performance. In this study, room temperature load capacity tests are performed on journal foil air bearings operating at 14,000 rpm. Different shaft and foil coating technologies such as plasma sprayed composites, ceramic, polymer and inorganic lubricant coatings are evaluated as foil bearing lubricants. The results indicate that bearing performance is improved through the individual use of the lubricants and treatments tested. Further, combining several solid lubricants together yielded synergistically better results than any material alone.

DellaCorte, Christopher↗
DOE OSTI2020

Efficiency Enhancing Anti-Frost Coatings for Heat Exchangers

As part of the Cyclotron Road program, the participant worked to develop geometric inorganic metamaterial coatings with functional surface energies that approached theoretical minimum. Most coating technologies chemically modify surfaces by applying a fluoropolymer to cause water to bead and roll off the surface, but the metamaterial coatings studied under this project were designed to modify local surface tension of a droplet, such that it pulls down on it at the bottom like a spring and as the droplet grows, the magnitude of the surface tension force increases to overwhelm droplet adhesion forces, causing the droplet to be repelled. These attributes make this technology ideally suited for heat transfer applications. This project’s coating experiments on evaporator coils inside an air conditioning unit demonstrated significant increases in energy efficiency.

32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATI↗
NASA NTRS1994

Plasma-Spray Metal Coating On Foam

Molds, forms, and other substrates made of foams coated with metals by plasma spraying. Foam might be ceramic, carbon, metallic, organic, or inorganic. After coat applied by plasma spraying, foam left intact or removed by acid leaching, conventional machining, water-jet cutting, or another suitable technique. Cores or vessels made of various foam materials plasma-coated with metals according to method useful as thermally insulating containers for foods, liquids, or gases, or as mandrels for making composite-material (matrix/fiber) parts, or making thermally insulating firewalls in automobiles.

Cranston, J.↗
NASA NTRS2002

Galvanic Liquid Applied Coating System for Protection of Embedded Steel Surfaces from Corrosion

The corrosion of reinforcing steel in concrete is an insidious problem for the Kennedy Space Center, government agencies, and the general public. Existing corrosion protection systems on the market are costly, complex, and time-consuming to install, require continuous maintenance and monitoring, and require specialized skills for installation. NASA's galvanic liquid-applied coating offers companies the ability to conveniently protect embedded steel rebar surfaces from corrosion. Liquid-applied inorganic galvanic coating contains one ore more of the following metallic particles: magnesium, zinc, or indium and may contain moisture attracting compounds that facilitate the protection process. The coating is applied to the outer surface of reinforced concrete so that electrical current is established between metallic particles and surfaces of embedded steel rebar; and electric (ionic) current is responsible for providing the necessary cathodic protection for embedded rebar surfaces.

Curran, Joseph↗
DOE OSTI2020

New Synthesis Strategies to Improve Co-Free LiNi0.5Mn0.5O2 Cathodes: Early Transition Metal d0 Dopants and Manganese Pyrophosphate Coating

In this work, we report solution-based doping and coating strategies to improve the electrochemical performance of the Co-free layered oxide cathode LiNi0.5Mn0.5O2 (LNMO). Small amounts of d0 dopants (e.g., Mo6+and Ti4+, 0.5-1 at. %) increase the cathode’s specific capacity, cycling stability, and rate capability. More specifically, a Mo-doped cathode with the nominal composition LiNi0.495Mn0.495Mo0.01O2 achieves a high reversible capacity of 180 mAh/g at 20 mA/g with good retention at higher rates (e.g., 120 mAh/g at 100 mA/g). Effects of 1 at.% Mo dopant on the cathode structure were studied using a suite of characterization tools including X-ray diffraction (XRD), Raman spectroscopy, and transmission electron microscopy (TEM). These measurements demonstrate that Mo6+ reduces Li+/Ni2+cation mixing and mitigates undesirable phase transformations near the cathode surface during cycling. This work also reports the use of an inorganic Mn2P2O7 coating which enhances cycling stability, presumably through formation of a stable cathode electrolyte interphase (CEI) layer. Overall, the synthesis approaches reported herein are quite general and can potentially be expanded to other high voltage LIB cathodes.

Co-free cathodes, d0 cation, pyrophosphate coating↗
NASA NTRS1971

Investigation of environmental effects on coatings for thermal control of large space vehicles

The objective of significantly advancing the state-of-the-art of white, spacecraft-radiator coatings has been realized in a comprehensive goal-oriented, pigmented-coatings research program. Considered were inorganic pigments and coatings, silicone polymers and coatings, the design and construction of a combined ultraviolet-plus-proton irradiation facility, the development of zinc orthotitanate pigment and coatings, and the effects on several low alpha sub s/epsilon paints of combined ultraviolet and proton irradiation.

Zerlaunt, G. A.↗
DOE OSTI2022

Observation of an Orientational Glass in a Superlattice of Elliptically-Faceted CdSe Nanocrystals

Extensive prior work has shown that colloidal inorganic nanocrystals coated with organic ligand shells can behave as artificial atoms and, as such, form superlattices with different crystal structures and packing densities. Although ordered superlattices present a high degree of long-range positional order, the relative crystallographic orientation of the inorganic nanocrystals with respect to each other tends to be random. Recent works have shown that superlattices can achieve orientational alignment through combinations of nanocrystal faceting and ligand modification, as well as selective metal particle attachment to particular facets. These studies have focused on the assembly of high-symmetry nanocrystals, such as cubes and cuboctahedra. In this work, we study the assembly of elliptically faceted CdSe/CdS core/shell nanocrystals with one distinctive crystallographic orientation along the major elliptical axis. We show that the nanocrystals form an unexpectedly well-ordered translational superlattice, with a degree of order comparable to that achieved with higher-symmetry nanocrystals. Additionally, we show that, due to the particles' faceted shape, the superlattice is characterized by an orientational glass phase in which only certain orientations are possible due to entropically frustrated crystallization. In this phase, the nanocrystals do not exhibit a local orientational ordering but rather have distinct orientations that emerge at different locations within the same domain. The distinct orientations are a result of a facet-to-facet lock-in mechanism that occurs during the self-assembly process. These facet-to-facet alignments force the nanocrystals to tilt on different lattice planes forming different projections that we termed apparent polydispersity. Our experimental realization of an orientational glass phase for multifaceted semiconducting nanocrystals can be used to investigate how this phase is formed and how it can be utilized for potential optical, electrical, and thermal transport applications.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2023

High Strength, Encapsulated, Commercially Useful Components and Particles Made from Coal Combustion Residuals

This project has developed and demonstrated two high-volume applications for Coal Combustion Residuals (CCR) with annual usage on the order of billions of pounds. The CCR is encapsulated in a recently developed water-impervious inorganic resin coating to reduce leaching of toxic elements from CCR by more than 80% as a first step. Target commercial applications demonstrated for the encapsulated CCR were as reinforcement for high-strength structural columns composed of CCR embedded in a ceramic matrix and as filler in high-volume plastics such as polypropylene. The encapsulated particles produced columns with properties superior to concrete, and a 30% to 50% improvement in stiffness over current fillers in plastics. CCR from bituminous and lignite coal was evaluated and shown to provide high performance, with the bituminous CCR producing the strongest columns and the lignite-based CCR provided the best performance as coated filler in polypropylene. The two-year project advanced both material systems from a Technology Readiness Level (TRL) of 2 to TRL 4.

01 COAL, LIGNITE, AND PEAT↗