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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 109 records · Page 6
All sourcesNASA NTRSDOE OSTI
NASA NTRS2011

In Situ Guided Wave Structural Health Monitoring System

Aircraft engine rotating equipment operates at high temperatures and stresses. Noninvasive inspection of microcracks in those components poses a challenge for nondestructive evaluation. A low-cost, low-profile, high-temperature ultrasonic guided wave sensor was developed that detects cracks in situ. The transducer design provides nondestructive evaluation of structures and materials. A key feature of the sensor is that it withstands high temperatures and excites strong surface wave energy to inspect surface and subsurface cracks. The sol-gel bismuth titanate-based surface acoustic wave (SAW) sensor can generate efficient SAWs for crack inspection. The sensor is very thin (submillimeter) and can generate surface waves up to 540 C. Finite element analysis of the SAW transducer design was performed to predict the sensor behavior, and experimental studies confirmed the results. The sensor can be implemented on structures of various shapes. With a spray-coating process, the sensor can be applied to the surface of large curvatures. It has minimal effect on airflow or rotating equipment imbalance, and provides good sensitivity.

Zhao, George↗
NASA NTRS2003

NASA Tech Briefs, June 2003

Topics covered include: Nulling Infrared Radiometer for Measuring Temperature; The Ames Power Monitoring System; Hot Films on Ceramic Substrates for Measuring Skin Friction; Probe Without Moving Parts Measures Flow Angle; Detecting Conductive Liquid Leaking from Nonconductive Pipe; Adaptive Suppression of Noise in Voice Communications; High-Performance Solid-State W-Band Power Amplifiers; Microbatteries for Combinatorial Studies of Conventional Lithium-Ion Batteries; Correcting for Beam Aberrations in a Beam-Waveguide Antenna; Advanced Rainbow Solar Photovoltaic Arrays; Metal Side Reflectors for Trapping Light in QWIPs; Software for Collaborative Engineering of Launch Rockets; Software Assists in Extensive Environmental Auditing; Software Supports Distributed Operations via the Internet; Software Estimates Costs of Testing Rocket Engines; yourSky: Custom Sky-Image Mosaics via the Internet; Software for Managing Inventory of Flight Hardware; Lower-Conductivity Thermal-Barrier Coatings; Process for Smoothing an Si Substrate after Etching of SiO2; Flexible Composite-Material Pressure Vessel; Treatment to Destroy Chlorohydrocarbon Liquids in the Ground; Noncircular Cross Sections Could Enhance Mixing in Sprays; Small, Untethered, Mobile Roots for Inspecting Gas Pipes; Paint-Overspray Catcher; Preparation of Regular Specimens for Atom Probes; Inverse Tomo-Lithography for Making Microscopic 3D Parts; Predicting and Preventing Incipient Flameout in Combustors; MEMS-Based Piezoelectric/Electrostatic Inchworm Actuator; Metallized Capillaries as Probes for Raman Spectroscopy; Adaptation of Mesoscale Weather Models to Local Forecasting; Aerodynamic Design using Neural Networks; Combining Multiple Gyroscope Outputs for Increased Accuracy; and Improved Collision-Detection Method for Robotic Manipulator.

Source record↗
NASA NTRS2012

Photoacoustic Optical Properties at UV, VIS, and near IR Wavelengths for Laboratory Generated and Winter Time Ambient Urban Aerosols

We present the laboratory and ambient photoacoustic (PA) measurement of aerosol light absorption coefficients at ultraviolet wavelength (i.e., 355 nm) and compare with measurements at 405, 532, 870, and 1047 nm. Simultaneous measurements of aerosol light scattering coefficients were achieved by the integrating reciprocal nephelometer within the PA's acoustic resonator. Absorption and scattering measurements were carried out for various laboratory generated aerosols, including salt, incense, and kerosene soot to evaluate the instrument calibration and gain insight on the spectral dependence of aerosol light absorption and scattering. Ambient measurements were obtained in Reno, Nevada, between 18 December 2009 and 18 January 2010. The measurement period included days with and without strong ground level temperature inversions, corresponding to highly polluted (freshly emitted aerosols) and relatively clean (aged aerosols) conditions. Particulate matter (PM) concentrations were measured and analyzed with other tracers of traffic emissions. The temperature inversion episodes caused very high concentration of PM (sub 2.5) and PM( sub 10) (particulate matter with aerodynamic diameters less than 2.5 micrometers and 10 micrometers, respectively) and gaseous pollutants: carbon monoxide (CO), nitric oxide (NO), and nitrogen dioxide (NO2). The diurnal change of absorption and scattering coefficients during the polluted (inversion) days increased approximately by a factor of two for all wavelengths compared to the clean days. The spectral variation in aerosol absorption coefficients indicated a significant amount of absorbing aerosol from traffic emissions and residential wood burning. The analysis of single scattering albedo (SSA), Angstrom exponent of absorption (AEA), and Angstrom exponent of scattering (AES) for clean and polluted days provides evidences that the aerosol aging and coating process is suppressed by strong temperature inversion under cloudy conditions. In general, measured UV absorption coefficients were found to be much larger for biomass burning aerosol than for typical ambient aerosols.

absorptivity↗
NASA NTRS2015

NASA-427: A New Aluminum Alloy

NASA's Marshall Space Flight Center researchers have developed a new, stronger aluminum alloy, ideal for cast aluminum products that have powder or paint-baked thermal coatings. With advanced mechanical properties, the NASA-427 alloy shows greater tensile strength and increased ductility, providing substantial improvement in impact toughness. In addition, this alloy improves the thermal coating process by decreasing the time required for heat treatment. With improvements in both strength and processing time, use of the alloy provides reduced materials and production costs, lower product weight, and better product performance. The superior properties of NASA-427 can benefit many industries, including automotive, where it is particularly well-suited for use in aluminum wheels.

Nabors, Sammy A.↗
NASA NTRS2016

Impact Toughness and Heat Treatment for Cast Aluminum

A method for transforming a cast component made of modified aluminum alloy by increasing the impact toughness coefficient using minimal heat and energy. The aluminum alloy is modified to contain 0.55%-0.60% magnesium, 0.10%-0.15% titanium or zirconium, less than 0.07% iron, a silicon-tomagnesium product ratio of 4.0, and less than 0.15% total impurities. The shortened heat treatment requires an initial heating at 1,000deg F. for up to I hour followed by a water quench and a second heating at 350deg F. to 390deg F. for up to I hour. An optional short bake paint cycle or powder coating process further increase.

Lee, Jonathan A↗
NASA NTRSDate not supplied

Influence of evaporation rate and chamber pressure on the FUV reflectance and physical characteristics of aluminum films

Space telescopes for studying astrophysical phenomena from the far ultraviolet (FUV) to the near infrared (NIR) require durable mirror coatings with high and uniform reflectance over a very broad spectral region. While coatings for the optical and NIR region are well developed with proven performance, the FUV band presents significant challenges, particularly below 115 nm. Recent developments in physical vapor deposition (PVD) coating processes of aluminum mirrors that are protected with a metal-fluoride overcoat to prevent oxidation (such as LiF, MgF2, or AlF3) have improved reflectance in the FUV. While the emphasis in these studies has been placed on improving the deposition conditions of the metal-fluoride overcoats, less attention has been devoted to how deposition parameters (such as vacuum conditions or deposition rates) may affect the quality of the aluminum mirrors. This paper presents characterization of Al+MgF2 coupons made by flash evaporation of aluminum followed by resistive evaporation of MgF2. Samples were manufactured under a variety of processing conditions and the relationship between processing variables and mirror FUV reflectivity is analyzed. Performance characterization was based on the measured near-normal reflectance in the FUV (90-180 nm), and normal-incidence transmittance in the visible was done to analyze the possible presence of pinholes in the mirror. We demonstrated pinhole-free Al/MgF2 mirrors deposited at room temperature with a reflectivity of 0.91 at 122 nm wavelength. This reflectivity enhancement was achieved solely through parameter optimization.

Manuel A. Quijada↗
NASA NTRSDate not supplied

Influence of Evaporation Rate and Chamber Pressure on the FUV Reflectance and Physical Characteristics of Aluminum Films

Space telescopes for studying astrophysical phenomena from the far ultraviolet (FUV) to the near infrared (NIR) require durable mirror coatings with high and uniform reflectance over a very broad spectral region. While coatings for the optical and NIR region are well developed with proven performance, the FUV band presents significant challenges, particularly below 115 nm. Recent developments in physical vapor deposition (PVD) coating processes of aluminum mirrors that are protected with a metal-fluoride overcoat to prevent oxidation (such as LiF, MgF2, or AlF3) have improved reflectance in the FUV. While the emphasis in these studies has been placed on improving the deposition conditions of the metal-fluoride overcoats, less attention has been devoted to how deposition parameters (such as vacuum conditions or deposition rates) may affect the quality of the aluminum mirrors. This paper presents characterization of Al+MgF2 coupons made by flash evaporation of aluminum followed by resistive evaporation of MgF2. Samples were manufactured under a variety of processing conditions and the relationship between processing variables and mirror FUV reflectivity is analyzed. Performance characterization was based on the measured near-normal reflectance in the FUV (90-180 nm), and normal-incidence transmittance in the visible was done to analyze the possible presence of pinholes in the mirror. We demonstrated pinhole-free Al/MgF2 mirrors deposited at room temperature with a reflectivity of 0.91 at 122 nm wavelength. This reflectivity enhancement was achieved solely through parameter optimization.

FUV reflectance, aluminum, PVD, deposition rate, A↗
NASA NTRSDate not supplied

Femtosecond Laser-Structured Transparent Anti-Fog Polycarbonate for Visor Applications

AlchLight has developed transparent anti-fog superhydrophobic polycarbonates for spacesuit helmets using femtosecond pulsed laser surface patterning technology. In contrast to conventional complex chemical coating processes, our laser patterning permanently alters the intrinsic wetting property of polycarbonate with little change to its transparency. The processing procedure is studied and optimized to produce the ideal superhydrophobic property and transparency. We were able to obtain a high contact angle (>150°), small sliding angle (<10°), and high transmission (>70%) over the visible wavelengths for polycarbonates. The anti-fog effect was also investigated. This technology will have a range of applications in spacesuit, automotive, medical, energy, and sports industries.

Spacesuit↗
NASA NTRS1983

Process Sprays Uniforms Plasma Coatings

Composite-powder processing procedure developed along with plasma-spray parameters to achieve homogeneous, well-bonded, low-porosity, self-lubricating coatings. Multicomponent plasma coatings are applied without segretation of components.

Sliney, H. E.↗
NASA NTRS1998

Evaluation of Convergent Spray Technology(TM) Spray Process for Roof Coating Application

The overall goal of this project was to demonstrate the feasibility of(CST) Convergent Spray Technology (Trademark) for the roofing industry. This was accomplished by producing an environmentally compliant coating utilization recycled materials, a CST(Trademark) spray process portable application cart, and hand-held applicator with a CST(Trademark) spray process nozzle. The project culminated with application of this coating to a nine hundred sixty square foot metal for NASA Marshall Space Flight Center (MSFC) in Huntsville, Alabama.

COATINGS↗
NASA NTRS2012

Friction modifier using adherent metallic multilayered or mixed element layer conversion coatings

A process for creating conversion coatings and spin, drawing, and extrusion finishes for surfaces, wherein the conversion coatings and spin, drawing, and extrusion finishes contain potassium, phosphorus, nitrogen, silicon, and one or more non-alkaline metals. The process comprises forming a first aqueous solution of silicate, potassium hydroxide, and ammonium hydroxide; forming a second aqueous solution of water, phosphoric acid, ammonium hydroxide, an alkali metal hydroxide, and one or more non-alkaline metals, and then combining the first solution with the second solution to form a final solution. This final solution forms an anti-friction multi-layer conversion coating or a spin, drawing, and extrusion finish on a surface when applied to the surface, either directly or as an additive in lubricating fluids.

Schramm, Harry F.↗
NASA NTRS2013

Friction Modifier Using Adherent Metallic Multilayered or Mixed Element Layer Conversion Coatings

A process for creating conversion coatings and spin, drawing, and extrusion finishes for surfaces, wherein the conversion coatings and spin, drawing, and extrusion finishes contain potassium, phosphorus, nitrogen, and one or more non-alkaline metals and/or one or more metalloids. The process comprises forming an aqueous solution of water, phosphoric acid or sulfuric acid, ammonium hydroxide, an alkali metal hydroxide, and one or more non-alkaline metals and/or one or more metalloids. The aqueous solution forms an anti-friction multilayer conversion and/or mixed element coating or a spin, drawing, and extrusion finish on a surface when applied to the surface, either directly without the use of applied external electromotive force, or as an additive in lubricating fluids.

Schramm, Harry F.↗
NASA NTRS1982

Processing of fused silicide coatings for carbon-based materials

The processing and oxidation resistance of fused Al-Si and Ni-Si slurry coatings on ATJ graphite was studied. Ni-Si coatings in the 70 to 90 percent Si range were successfully processed to melt, wet, and bond to the graphite. The molten coatings also infiltrated the porosity in graphite and reacted with it to form SiC in the coating. Cyclic oxidation at 1200 C showed that these coatings were not totally protective because of local attack of the substrate, due to the extreme thinness of the coatings in combination with coating cracks.

Smialek, J. L.↗
NASA NTRS1983

Processing of fused silicide coatings for carbon-based materials

The processing and oxidation resistance of fused Al-Si and Ni-Si slurry coatings on ATJ graphite was studied. Ni-Si coatings in the 70 to 90 percent Si range were successfully processed to melt, wet, and bond to the graphite. The molten coatings also infiltrated the porosity in graphite and reacted with it to form SiC in the coating. Cyclic oxidation at 1200 C showed that these coatings were not totally protective because of local attack of the substrate, due to the extreme thinness of the coatings in combination with coating cracks. Previously announced in STAR as N83-27019

Smialek, J. L.↗
NASA NTRS2001

Process for ultra smooth diamond coating on metals and uses thereof

The present invention provides a new process to deposit well adhered ultra smooth diamond films on metals by adding nitrogen gas to the methane/hydrogen plasma created by a microwave discharge. Such diamond coating process is useful in tribological/wear resistant applications in bio-implants, machine tools, and magnetic recording industry.

Vohra, Yogesh K.↗
NASA NTRS2007

Coating Carbon Fibers With Platinum

A process for coating carbon fibers with platinum has been developed. The process may also be adaptable to coating carbon fibers with other noble and refractory metals, including rhenium and iridium. The coated carbon fibers would be used as ingredients of matrix/fiber composite materials that would resist oxidation at high temperatures. The metal coats would contribute to oxidation resistance by keeping atmospheric oxygen away from fibers when cracks form in the matrices. Other processes that have been used to coat carbon fibers with metals have significant disadvantages: Metal-vapor deposition processes yield coats that are nonuniform along both the lengths and the circumferences of the fibers. The electrical resistivities of carbon fibers are too high to be compatible with electrolytic processes. Metal/organic vapor deposition entails the use of expensive starting materials, it may be necessary to use a furnace, and the starting materials and/or materials generated in the process may be hazardous. The present process does not have these disadvantages. It yields uniform, nonporous coats and is relatively inexpensive. The process can be summarized as one of pretreatment followed by electroless deposition. The process consists of the following steps: The surfaces of the fiber are activated by deposition of palladium crystallites from a solution. The surface-activated fibers are immersed in a solution that contains platinum. A reducing agent is used to supply electrons to effect a chemical reduction in situ. The chemical reduction displaces the platinum from the solution. The displaced platinum becomes deposited on the fibers. Each platinum atom that has been deposited acts as a catalytic site for the deposition of another platinum atom. Hence, the deposition process can also be characterized as autocatalytic. The thickness of the deposited metal can be tailored via the duration of immersion and the chemical activity of the solution.

Effinger, Michael R.↗
NASA NTRS2018

Fatigue Life of a NiCr-Coated Powder Metallurgy Disk Superalloy After Varied Processing and Exposures

A protective ductile NiCr coating has shown promise to mitigate oxidation and corrosion attack on superalloy disk alloys. The effects of this coating on fatigue life and failure modes of the disk superalloy are an important concern. The objective of this study was to investigate the fatigue life and failure modes of disk superalloy specimens protected by this coating, using varied pre-coating and post-coating processes. Cylindrical gage fatigue specimens of a powder metallurgy-processed disk superalloy were grit blast or wet blast before being coated with a ductile NiCrY coating, then shot peened at low or medium levels after coating. All were then heat treated, some exposed, and finally all were subjected to fatigue at high temperature. The effects of varied pre-coating treatment, post-coating shot peening, and oxidation plus hot corrosion exposures on fatigue life with the coating were compared.

coating↗