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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 19 records
All sourcesNASA NTRSDOE OSTI
NASA NTRS1999

Space Environmental Effects on Colored Coatings and Anodizes

Colored coatings and anodizes are used on spacecraft as markers and astronaut visual aids. These materials must be stable in the space environment and withstand atomic oxygen, ultraviolet radiation, particulate radiation, thermal cycling, and high vacuum without significant change in optical and mechanical properties. A variety of colored coatings and anodizes have been exposed to simulated space environments at Marshall Space Flight Center and also actual space environment as part of the Passive Optical Sample Assembly (POSA) - I flight experiment. Colored coatings were developed by AZ Technology, Huntsville, AL, under a NASA contract for International Space Station (ISS). These include yellow, red, blue, and black paints suitable for Extra-Vehicular Activity (EVA) visual aids and ISS emblems. AaChron, Inc., Minneapolis, MN, developed stable colored anodizes, also in yellow, red, blue, and black, for astronaut visual aids. These coatings were exposed in the laboratory to approximately 550 equivalent sun-hours of solar ultraviolet radiation and approximately 1 x 10(exp 21) atoms/sq cm of atomic oxygen in vacuum. The AZ Technology yellow colored coating, designated TMS800IY, and all four AaChron colored anodizes were flown on POSA-I. POSA-I was a Risk Mitigation Experiment for ISS. It was attached to the exterior of the Mir space station docking module by EVA and was exposed for 18 months. The laboratory-simulated space environment, the natural space environment and the unique environment of an orbiting, active space station and their effects on these developmental materials are discussed.

Kamenetzky, Rachel R.↗
NASA NTRS1998

High-absorptance high-emittance anodic coating

A colored anodic coating for use on surfaces of substrates, e.g. aluminum substrates in which it is desirable to maintain a high solar absorptance (a) and a high infrared emittance (e), particularly in low earth orbit space environments. This anodic coating is preferably a dark colored coating, and even more preferably a black coating. This coating allows a touch temperature within an acceptable design range to preclude burning of an astronaut in case of contact, but also allows a solar radiation absorption in an amount such that an a/e ratio of unity is achieved. The coating of the invention comprises a first layer in the form of an acid anodized colored anodic layer for achieving a high solar absorptance and a second or high emittance layer in the form of a clear acid anodized layer for achieving a high emittance. The entire coating is quite thin, e.g. 1-2 mils and is quite stable in a hostile space environment of the type encountered in a low earth orbit. The coating is obtained by first creating the high emittance clear anodized coating on the metal surface followed by anodizing using a colored anodizing process.

Le, Huong Giang↗
NASA NTRS1999

High-absorptance high-emittance anodic coating

A colored anodic coating for use on surfaces of substrates, e.g. aluminum substrates in which it is desirable to maintain a high solar absorptance (.alpha.) and a high infrared emittance (.epsilon.), particularly in low earth orbit space environments. This anodic coating is preferably a dark colored coating, and even more preferably a black coating. This coating allows a touch temperature within an acceptable design range to preclude burning of an astronaut in case of contact, but also allows a solar radiation absorption in an amount such that an .alpha./.epsilon. ratio of unity is achieved. The coating of the invention comprises a first layer in the form of an acid anodized colored anodic layer for achieving a high solar absorptance and a second or high emittance layer in the form of a clear acid anodized layer for achieving a high emittance. The entire coating is quite thin, e.g. 1-2 mils and is quite stable in a hostile space environment of the type encountered in a low earth orbit. The coating is obtained by first creating the high emittance clear anodized coating on the metal surface followed by anodizing using a colored anodizing process.

Le, Huong Giang↗
DOE OSTI2014

Noncomposite Counterelectrode Development

New counter electrode materials under development at NREL have the potential to positively impact electrochromic window technology. The current generation of nanocomposite materials is designed to provide rapid transport of lithium ions to nanoparticles of anodic coloring materials. They may improve the coloration efficiency of the entire films stack while also improving the speed and depth of coloration. We expect an added benefit of greater film durability. To date, encouraging results have been obtained in the laboratory. Performance and durability tests will be carried out to characterize any improvements obtained as a result of the new counter electrode materials. In addition to process improvement, the project also has the secondary goal of improving the basic understanding of the electrochromic process in Sage?s counter electrode.

32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATI↗
NASA NTRS1990

Finding Platinum-Coating Gaps On Titanium Anodes

Simple procedure makes gaps visible to eye. New gap-detection method consists of plating thin layer of non-silver-colored metal like copper or gold on anode. Contrast in color between plated metal and bare anode material makes gaps stand out. If anode passes inspection, copper or gold plate removable by reversal of test-plating current. Remains to be determined whether test plating and removal damages anode. New method simpler and more economical than previous attempts to identify gaps in platinum.

Bodemeijer, Ronnald↗
DOE OSTI2022

Black-to-Transmissive dual polymer complementary electrochromics with high coloration efficiency

In a complementary electrochromic device (ECD), both the anode and the cathode can synergistically change color in response to an electrical bias, allowing for a high coloration efficiency. Complementary ECD that can switch from black to transmissive state is rare, due to the difficulty of pairing two electrochromic electrodes. In this study, we report the construction of high coloration efficiency complementary ECDs by pairing polyazoisoindigo (PAI), an n-type electrochromic polymer that undergoes green-to-transmissive switching, with p-type magenta (ECP-M) and red (ECP-R) electrochromic polymers to obtain black-to-transmissive ECD. Physical modeling tool, COMSOL, is introduced for complementary color matching. Through balancing the charge densities of two electrochromic electrodes, black-to-transmissive ECDs with record-high coloration efficiencies of 688 cm 2 /C and 437 cm 2 /C have been achieved for PAI|ECP-M and PAI|ECP-R, respectively. This study provides a general protocol for the design and fabrication of complementary ECDs.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2014

Measurement of anode surface temperature in carbon nanomaterial production by arc discharge method

Highlights: • We measured the temperature of anode surface by two-color pyrometry combined with a high speed camera successfully. • Growth temperature of pyrolytic graphite, MWNTs, and nano-graphite particles were in ranges of 2400–2600 K, 2600–2700 K, and 2700–3500 K, respectively. • High temperature contributes to form thermodynamically unstable material. - Abstract: Nano-graphite particles, multi-wall carbon nanotube (MWNT), and pyrolytic graphite were prepared at different positions of the anode surface in an arc discharge. Graphite electrodes were employed for the arc discharge under helium environment at atmospheric pressure. Nano-sized carbon products were characterized by scanning electron microscopy and transmission electron microscopy. During the arc discharge, two-color pyrometry combined with a high-speed camera was conducted to measure the temperature distribution of the anode surface. The growth temperature of pyrolytic graphite, MWNT, and nano-graphite particles were in the ranges of 2400–2600 K, 2600–2700 K, and 2700–3500 K, respectively. The local temperature of anode surface is a critical parameter to determine the products with different morphologies. The formation mechanism of these carbon nanomaterials is suggested based on the local temperature of anode surface and their thermodynamic stability.

36 MATERIALS SCIENCE↗
DOE OSTI2016

AZO/Ag/AZO anode for resonant cavity red, blue, and yellow organic light emitting diodes

Indium tin oxide (ITO) is the transparent electrode of choice for organic light-emitting diodes (OLEDs). Replacing ITO for cost and performance reasons is a major drive across optoelectronics. In this work, we show that changing the transparent electrode on red, blue, and yellow OLEDs from ITO to a multilayer buffered aluminium zinc oxide/silver/aluminium zinc oxide (AZO/Ag/AZO) substantially enhances total output intensity, with better control of colour, its constancy, and intensity over the full exit hemisphere. The thin Ag containing layer induces a resonant cavity optical response of the complete device. This is tuned to the emission spectra of the emissive material while minimizing internally trapped light. A complete set of spectral intensity data is presented across the full exit hemisphere for each electrode type and each OLED colour. Emission zone modelling of output spectra at a wide range of exit angles to the normal was in excellent agreement with the experimental data and hence could, in principle, be used to check and adjust production settings. These multilayer transparent electrodes show significant potential for both eliminating indium from OLEDs and spectrally shaping the emission.

71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSIC↗
DOE OSTI2014

Electrochemical fabrication and optical properties of porous tin oxide films with structural colors

Photonic crystals with porous features not only provide the capability to control light but also enable structural colors that are environmentally sensitive. Here, we report a novel kind of tin oxide-based photonic crystal featuring periodically arranged air pores fabricated by the periodic anodization of tin foil. The existence of a photonic band gap in the fabricated structure is verified by its vivid color, and its reflective spectra which are responsive to environmental stimuli. Furthermore, the sample colors (i.e., the photonic band gap positions) can be easily adjusted by manipulating the anodization parameters. The theoretical modeling results of these tin oxide photonic crystals agree well with the reported experimental ones.

75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND↗
DOE OSTI2025

In situ studies of a molten metal anode ablation in a nearly atmospheric pressure DC arc

A DC arc with a meltable metal anode in a near-atmospheric pressure hydrocarbon gas is an emerging method for producing single-walled carbon nanotubes (SWCNTs). In these systems, evaporation of the molten metal anode determines the formation of catalyst seed particles needed for SWCNT growth, and therefore, should be monitored, controlled, and optimized. Evaluating the anode ablation rate by weighing the anode before and after a synthesis run is unfeasible due to anode carburization in the hydrocarbon atmosphere. To overcome this, we implemented a high-speed, 2D, 2-color pyrometry for reliable temperature measurements of the molten anode in a DC arc. The obtained temperature fields were used to calculate the anode ablation rates. Results showed the importance of resolving the arc and molten pool dynamics, as well as addressing the issue of reflections. Furthermore, significant changes in ablation rates were revealed upon addition of CH 4 , which must be considered when scaling up the production of SWCNTs.

Marangoni↗
DOE OSTI2015

Tunable color parallel tandem organic light emitting devices with carbon nanotube and metallic sheet interlayers

Parallel tandem organic light emitting devices (OLEDs) were fabricated with transparent multiwall carbon nanotube sheets (MWCNT) and thin metal films (Al, Ag) as interlayers. In parallel monolithic tandem architecture, the MWCNT (or metallic films) interlayers are an active electrode which injects similar charges into subunits. In the case of parallel tandems with common anode (C.A.) of this study, holes are injected into top and bottom subunits from the common interlayer electrode; whereas in the configuration of common cathode (C.C.), electrons are injected into the top and bottom subunits. Both subunits of the tandem can thus be monolithically connected functionally in an active structure in which each subunit can be electrically addressed separately. Our tandem OLEDs have a polymer as emitter in the bottom subunit and a small molecule emitter in the top subunit. We also compared the performance of the parallel tandem with that of in series and the additional advantages of the parallel architecture over the in-series were: tunable chromaticity, lower voltage operation, and higher brightness. Finally, we demonstrate that processing of the MWCNT sheets as a common anode in parallel tandems is an easy and low cost process, since their integration as electrodes in OLEDs is achieved by simple dry lamination process.

71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSIC↗
NASA NTRS1999

Modified Truncated Cone Target Hyperthermal Atomic Oxygen Test Results

The modified truncated cone target is a docking target planned for use on the International Space Station. The current design consists of aluminum treated with a black dye anodize, then crosshairs are laser etched for a silvery color. Samples of the treated aluminum were exposed to laboratory simulation of atomic oxygen and ultraviolet radiation to determine if significant degradation might occur. Durability was evaluated based on the contrast ratio between the black and silvery white areas of the target. Degradation of optical properties appeared to level off after an initial period of exposure to atomic oxygen. The sample that was not alodined according to MIL-C-5541, type 1A, performed better than alodined samples.

Vaughn, J. A.↗
DOE OSTI2020

Color-neutral, semitransparent organic photovoltaics for power window applications

Semitransparent organic photovoltaic cells (ST-OPVs) are emerging as a solution for solar energy harvesting on building facades, rooftops, and windows. However, the trade-off between power-conversion efficiency (PCE) and the average photopic transmission (APT) in color-neutral devices limits their utility as attractive, power-generating windows. A color-neutral ST-OPV is demonstrated by using a transparent indium tin oxide (ITO) anode along with a narrow energy gap nonfullerene acceptor near-infrared (NIR) absorbing cell and outcoupling (OC) coatings on the exit surface. The device exhibits PCE = 8.1 ± 0.3% and APT = 43.3 ± 1.2% that combine to achieve a light-utilization efficiency of LUE = 3.5 ± 0.1%. Commission Internationale d’eclairage chromaticity coordinates of (0.38, 0.39), a color-rendering index of 86, and a correlated color temperature of 4,143 K are obtained for simulated AM1.5 illumination transmitted through the cell. Using an ultrathin metal anode in place of ITO, we demonstrate a slightly green-tinted ST-OPV with PCE = 10.8 ± 0.5% and APT = 45.7 ± 2.1% yielding LUE = 5.0 ± 0.3% These results indicate that ST-OPVs can combine both efficiency and color neutrality in a single device.

14 SOLAR ENERGY↗
DOE OSTI2015

Fabrication of one-dimensional alumina photonic crystals by anodization using a modified pulse-voltage method

Highlights: • The alumina multilayer structure with alternating high and low refractive index is fabricated. • This multilayer shows a strong photonic band gap (PBG) and vivid film colors. • The first PBG could be modulated easily by varying the duration time of constant high or low voltages. • Fabrication of the photonic crystal is obtained by directly electrochemical anodization. • The formation mechanism of multilayer is also discussed. - Abstract: The alumina nanolayer structure with alternating high and low porosities is conveniently fabricated by applying a modified pulse voltage waveform with constant high and low voltage. This structure shows the well-defined layer in a long-range structural periodicity leads to a strong photonic band gap (PBG) from visible to near infrared and brilliant film colors. Compared with the previous reported tuning method, this method is more simple and flexible in tuning the PBG of photonic crystals (PCs). The effect of duration time of high, low and 0 V voltages on PBG is discussed. The first PBG could be modulated easily from the visible to near infrared region by varying the duration time of constant high or low voltages. It is also found that the 0 V lasting for appropriate time is helpful to improve the quality of the PCs. The formation mechanism of multilayer is also discussed.

36 MATERIALS SCIENCE↗
DOE OSTI2015

Environmental resistance of oxide tags fabricated on 304L stainless steel via nanosecond pulsed laser irradiation

Nanosecond pulsed laser irradiation was used to fabricate colored, mechanically robust oxide “tags” on 304L stainless steel. Immersion in simulated seawater solution, salt fog exposure, and anodic polarization in a 3.5% NaCl solution were employed to evaluate the environmental resistance of these oxide tags. Single layer oxides outside a narrow thickness range (~ 100–150 nm) are susceptible to dissolution in chloride containing environments. The 304L substrates immediately beneath the oxides corrode severely—attributed to Cr-depletion in the melt zone during laser processing. For the first time, multilayered oxides were fabricated with pulsed laser irradiation in an effort to expand the protective thickness range while also increasing the variety of film colors attainable in this range. Layered films grown using a laser scan rate of 475 mm/s are more resistant to both localized and general corrosion than oxides fabricated at 550 mm/s. Furthermore, in the absence of pre-processing to mitigate Cr-depletion, layered films can enhance environmental stability of the system.

54 ENVIRONMENTAL SCIENCES↗
DOE OSTI2022

Revealing nanomechanical deformation at the interface and degradation in all-thin-film inorganic electrochromic devices

Recently, progress in electrochromic (EC) devices has been made in optimizing electrode and device configurations and performance. However, the ion insertion/de-insertion induced charge transfer (CT) nanomechanical effect has remained unexplored, i.e., repetitive electrode size changes at the nanoscale and stress/strain generated during electrochemical cycling, which is the focus of this work due to its intimate correlation with the elastic and plastic deformation at the interface. Considering the intervalence electrons, excellent electrochemical kinetics, and dramatic color changes, tungsten oxide (WO 3 ) and nickel oxide (NiO) films are configured as the EC cathode and anode materials, respectively, within a full device. Upon extended cycles (>10 000), the void generation and delamination that occurred at the interface account for performance decay. Encouraged by the findings, nanoindentation mechanical tests and electrical kelvin probe force microscopy were employed to investigate the CT induced effects at the interface. There is a dramatic increase of up to 45% in the elastic Young's modulus in colored/charged WO 3 at ~40 mC cm -2 . Here, the correlation between CT and synergistic mechanical effect is interpreted by the Lippman equation. Interestingly, despite the charged state (colored; lithiated) with a relatively flat morphology bringing an ~3.4 times higher electrostatic surface potential, the electrical work function unexpectedly decreases, arising from the dominant effect of the dipole layer potential over the chemical potential. The interatomic cohesive energy and equilibrium distance increase bury the seeds for mechanical deformation in the long run. This work provides fundamental insights into electro-chemo mechanics and interdisciplinary concerted interfacial effects at the nano/atomic level. The dependence of surface potential, stress, work function, and cohesive energy on electrochemical kinetics has been interpreted.

36 MATERIALS SCIENCE↗
DOE OSTI2021

Metallic and porous Ti nanorod arrays for visible-IR light absorption and dendrite-free stable lithium-metal batteries

It is still a challenging task to prepare highly porous nanorod arrays of metals formed on substrates for optical and energy storage applications. Herein, we demonstrate the design and synthesis of black color, metallic and highly porous Ti nanorod arrays as novel current collectors for dendrite-free and highly stable Li-metal anodes. The high porosity of metallic nanorod arrays provides numerous heterogeneous nucleation sites and huge contact area and large space for the accommodation of Li metal. The conductive metallic Ti nanorod arrays enhance electrode integration. Effectively, it eliminates formation Li dendrites and demonstrates superior cycling stability over 300 cycles. Additionally, the unique porous structures of the nanorod arrays can decrease the amplitude of forced vibration in narrow space leading to light absorption. Interestingly, the metal is black instead of metallic color. The black metallic nanorod arrays can absorb more than 96% of both visible and infra-red lights. Furthermore, this black color metallic porous nanorod arrays may find additional applications in aerospace, energy, biomedical, defence, and chemical industries.

25 ENERGY STORAGE↗