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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 919 records · Page 51
All sourcesNASA NTRSDOE OSTI
NASA NTRS2002

Micro-Raman Analysis of Irradiated Diamond Films

Owing to its unique and robust physical properties, diamond is a much sought after material for use in advanced technologies such as Microelectromechanical Systems (MEMS). The volume and weight savings promised by MEMS-based devices are of particular interest to spaceflight applications. However, much basic materials science research remains to be completed in this field. Results of micro-Raman analysis of proton (1015 - 1017 H+/cm2 doses) irradiated chemical vapor deposited (CVD) diamond reveals that the microstructure is retained even after high radiation exposure.

Newton, R. 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 NTRS2009

Method of plasma enhanced chemical vapor deposition of diamond using methanol-based solutions

Briefly described, methods of forming diamond are described. A representative method, among others, includes: providing a substrate in a reaction chamber in a non-magnetic-field microwave plasma system; introducing, in the absence of a gas stream, a liquid precursor substantially free of water and containing methanol and at least one carbon and oxygen containing compound having a carbon to oxygen ratio greater than one, into an inlet of the reaction chamber; vaporizing the liquid precursor; and subjecting the vaporized precursor, in the absence of a carrier gas and in the absence in a reactive gas, to a plasma under conditions effective to disassociate the vaporized precursor and promote diamond growth on the substrate in a pressure range from about 70 to 130 Torr.

Tzeng, Yonhua↗
NASA NTRS2013

Recent Optical and SEM Characterization of Genesis Solar Wind Concentrator Diamond on Silicon Collector

One of the 4 Genesis solar wind concentrator collectors was a silicon substrate coated with diamond-like carbon (DLC) in which to capture solar wind. This material was designed for analysis of solar nitrogen and noble gases [1, 2]. This particular collector fractured during landing, but about 80% of the surface was recovered, including a large piece which was subdivided in 2012 [3, 4, 5]. The optical and SEM imaging and analysis described below supports the subdivision and allocation of the diamond-on-silicon (DOS) concentrator collector.

Allton, Judith H.↗
NASA NTRS2013

Plan for Subdividing Genesis Mission Diamond-on-Silicon 60000 Solar Wind Collector

NASA's Genesis solar wind sample return mission experienced an off nominal landing resulting in broken, albeit useful collectors. Sample 60000 from the collector is comprised of diamond-like-carbon film on a float zone (FZ) silicon wafer substrate Diamond-on-Silicon (DOS), and is highly prized for its higher concentration of solar wind (SW) atoms. A team of scientist at the Johnson Space Center was charged with determining the best, nondestructive and noncontaminating method to subdivide the specimen that would result in a 1 sq. cm subsample for allocation and analysis. Previous work included imaging of the SW side of 60000, identifying the crystallographic orientation of adjacent fragments, and devising an initial cutting plan.

Burkett, Patti J.↗
NASA NTRS2014

High Thermal Conductivity NARloy-Z-Diamond Composite Combustion Chamber Liner For Advanced Rocket Engines

Advanced high thermal conductivity materials research conducted at NASA Marshall Space Flight Center (MSFC) with state of the art combustion chamber liner material NARloy-Z showed that its thermal conductivity can be increased significantly by adding diamond particles and sintering it at high temperatures. For instance, NARloy-Z containing 40 vol. percent diamond particles, sintered at 975C to full density by using the Field assisted Sintering Technology (FAST) showed 69 percent higher thermal conductivity than baseline NARloy-Z. Furthermore, NARloy-Z-40vol. percent D is 30 percent lighter than NARloy-Z and hence the density normalized thermal conductivity is 140 percent better. These attributes will improve the performance and life of the advanced rocket engines significantly. By one estimate, increased thermal conductivity will directly translate into increased turbopump power up to 2X and increased chamber pressure for improved thrust and ISP, resulting in an expected 20 percent improvement in engine performance. Follow on research is now being conducted to demonstrate the benefits of this high thermal conductivity NARloy-Z-D composite for combustion chamber liner applications in advanced rocket engines. The work consists of a) Optimizing the chemistry and heat treatment for NARloy-Z-D composite, b) Developing design properties (thermal and mechanical) for the optimized NARloy-Z-D, c) Fabrication of net shape subscale combustion chamber liner, and d) Hot fire testing of the liner for performance. FAST is used for consolidating and sintering NARlo-Z-D. The subscale cylindrical liner with built in channels for coolant flow is also fabricated near net shape using the FAST process. The liner will be assembled into a test rig and hot fire tested in the MSFC test facility to determine performance. This paper describes the development of this novel high thermal conductivity NARloy-Z-D composite material, and the advanced net shape technology to fabricate the combustion chamber liner. Properties of optimized NARloy-Z-D composite material will also be presented.

Bhat, Biliyar N.↗
NASA NTRS2013

Diamond Nucleation Using Polyethene

The invention presents a simple, non-destructive and non-abrasive method of diamond nucleation using polyethene. It particularly describes the nucleation of diamond on an electrically viable substrate surface using polyethene via chemical vapor deposition (CVD) technique in a gaseous environment.

Morell, Gerardo↗
NASA NTRS2015

Numerical and Theoretical Considerations for the Design of the AVT-183 Diamond-Wing Experimental Investigations

A diamond-wing configuration has been developed to isolate and study blunt-leading edge vortex separation with both computations and experiments. The wing has been designed so that the results are relevant to a more complex Uninhabited Combat Air Vehicle concept known as SACCON. The numerical and theoretical development process for this diamond wing is presented, including a view toward planned wind tunnel experiments. This work was conducted under the NATO Science and Technology Organization, Applied Vehicle Technology panel. All information is in the public domain.

Boelens, Okko J.↗
NASA NTRS2016

Planar Field Emitters and High Efficiency Photocathodes Based on Ultrananocrystalline Diamond

A method of forming a field emitter comprises disposing a first layer on a substrate. The first layer is seeded with nanodiamond particles. The substrate with the first layer disposed thereon is maintained at a first temperature and a first pressure in a mixture of gases which includes nitrogen. The first layer is exposed to a microwave plasma to form a nitrogen doped ultrananocrystalline diamond film on the first layer, which has a percentage of nitrogen in the range of about 0.05 atom % to about 0.5 atom %. The field emitter has about 10.sup.12 to about 10.sup.14 emitting sites per cm.sup.2. A photocathode can also be formed similarly by forming a nitrogen doped ultrananocrystalline diamond film on a substrate similar to the field emitter, and then hydrogen terminating the film. The photocathode is responsive to near ultraviolet light as well as to visible light.

Sumant, Anirudha V.↗
NASA NTRS1993

Below Band-Gap Laser Ablation of Diamond for Transmission Electron Microscopy

A 248-nm excimer laser was used to thin naturally occurring type 1a diamond substrates at normal and glancing (22 deg) incidence. Perforation of a 250 micron thick substrate was achieved in about 15 minutes at normal incidence. Whilst the substrate thinned at glancing incidence was found to have large electron-transparent areas, that thinned at normal incidence required additional argon milling to achieve electron transparency. X-ray photoelectron spectroscopy of the back surface of the diamond failed to detect any graphite or glassy carbon, confirming that damage due to laser ablation occurs only at the incident surface. Samples prepared using this technique imaged in the transmission electron microscope were observed to have retained the nitrogen platelets

Posthill, J. B.↗
DOE OSTI2013

Diamond nucleation using polyethene

The invention presents a simple, non-destructive and non-abrasive method of diamond nucleation using polyethene. It particularly describes the nucleation of diamond on an electrically viable substrate surface using polyethene via chemical vapor deposition (CVD) technique in a gaseous environment.

36 MATERIALS SCIENCE↗
DOE OSTI2016

Planar field emitters and high efficiency photocathodes based on ultrananocrystalline diamond

A method of forming a field emitter comprises disposing a first layer on a substrate. The first layer is seeded with nanodiamond particles. The substrate with the first layer disposed thereon is maintained at a first temperature and a first pressure in a mixture of gases which includes nitrogen. The first layer is exposed to a microwave plasma to form a nitrogen doped ultrananocrystalline diamond film on the first layer, which has a percentage of nitrogen in the range of about 0.05 atom % to about 0.5 atom %. The field emitter has about 10.sup.12 to about 10.sup.14 emitting sites per cm.sup.2. A photocathode can also be formed similarly by forming a nitrogen doped ultrananocrystalline diamond film on a substrate similar to the field emitter, and then hydrogen terminating the film. The photocathode is responsive to near ultraviolet light as well as to visible light.

36 MATERIALS SCIENCE↗
DOE OSTI2016

Low-stress doped ultrananocrystalline diamond

Nanocrystalline diamond coatings exhibit stress in nano/micro-electro mechanical systems (MEMS). Doped nanocrstalline diamond coatings exhibit increased stress. A carbide forming metal coating reduces the in-plane stress. In addition, without any metal coating, simply growing UNCD or NCD with thickness in the range of 3-4 micron also reduces in-plane stress significantly. Such coatings can be used in MEMS applications.

36 MATERIALS SCIENCE↗
DOE OSTI2018

Phosphorus incorporation for n-type doping of diamond with (100) and related surface orientation

Apparatuses and methods are provided for manufacturing diamond electronic devices. The method includes at least one of the following acts: positioning a substrate in a plasma enhanced chemical vapor deposition (PECVD) reactor; controlling temperature of the substrate by manipulating microwave power, chamber pressure, and gas flow rates of the PECVD reactor; and growing phosphorus doped diamond layer on the substrate using a pulsed deposition comprising a growth cycle and a cooling cycle.

36 MATERIALS SCIENCE↗
DOE OSTI2019

Systems and methods for forming diamond heterojunction junction devices

A method of forming a p-n junction device comprises providing a base layer including a p-type diamond. A monolayer or few layer of a transition metal dichalcogenide (TMDC) is disposed on at least a portion of the base layer so as to form a heterojunction therebetween. The TMDC monolayer is an n-type layer such that the heterojunction between the intrinsic and p-type diamond base layer and the n-type TMDC monolayer is a p-n junction.

Sumant, Anirudha V.↗
DOE OSTI2013

Process for fabricating piezoelectrically actuated ultrananocrystalline diamond tip array integrated with ferroelectric or phase change media for high-density memory

A process for fabricating a piezoactuated storage device having a tip array and a memory media, which includes but is not limited to: etching the regions on the surface of the silicon wafer to produce substantially pyramidal etch pits by anisotropic etching or chemical etching with potassium hydroxide (KOH); growing an oxide layer on a top surface of the silicon wafer and in the substantially pyramidal etch pits to produce oxidation sharpening of the substantially pyramidal etch pits; forming an array of conductive tips of a nanocarbon film of nanostructured carbon material by deposition, wherein the nanostructured carbon material is ultrananocrystalline diamond (UNCD), ta-C, or diamond-like carbon films; and forming an oxygen diffusion barrier layer by deposition of a TiAl, TaAl, or any other oxygen diffusion barrier layer material on the nanocarbon film.

Auciello, Orlando H.↗