Feasibility of achieving two-electron K–O 2 batteries
A low-barrier, two-step reaction pathway for peroxide-based K–O chemistry is first realized without any catalysts under the inert argon atmosphere.
Chemistry↗
SEARCH · Engineering Papers
Results for “inert atmosphere”
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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Coal to Carbon Fiber (C2CF) Continuous Processing for High Value Composites (Final Report)
Coal tar is a condensed and recovered by-product of the coking of metallurgical coal for steel production. The heaviest fraction of distilled coal tar is an isotropic pitch largely used as a binder in the manufacturing of carbonaceous electrodes for primary aluminum smelting and in electric arc furnaces. Coal tar pitch offers high carbon yield upon carbonization. In this project, a process to convert the domestically sourced isotropic coal tar pitch, containing very low particulates (QI = 0.32 wt.%), to form flow-domain mesophase pitch amenable for melt spinning into precursor (green) fibers for carbon fiber, was developed and optimized. The final reproducible processing developed is reviewed in this report, along with several characterizations of the mesophase pitch. A final definition of the characteristics of a ‘spinnable’ mesophase pitch is presented. With this mesophase pitch, reproducible and stable multifilament melt spinning was developed, producing green fiber tows with filament diameters of approximately 20 m. The multifilament melt spinning was the most challenging aspect of the project and required the most effort. The best practices learned from this project for melt spinning are reviewed in this report. Once spun, the green fibers were oxidatively stabilized, carbonized and graphitized under inert gas atmosphere to form the final carbon fibers. Given the relatively high softening point of the mesophase pitch, no issues of interfilament fusion were observed during batch oxidation, and subsequent batch carbonization and graphitization went smoothly in all cases. An ~ 80 wt.% conversion of the green fiber mass to final carbon fiber was achieved. After graphitization, the carbon fibers showed high tensile moduli (most were ~ 600 GPa, or 87 Msi) consistent with commercially-available high-performance pitch-based carbon fiber. However, tensile strength and strain to failure were comparatively low. Further work to reduce defects in and on the fiber surfaces would increase these properties. SEM imaging of the graphitic fiber textures is presented herein. Rudimentary composites were fabricated from the carbon fibers and characterized showing similar modulus to baseline composites fabricated with commercial carbon fiber. Finally, a basic economic analysis was done showing the potential to increase the value of the isotropic coal tar pitch by up to 13.6 to 136 times based on a carbon fiber value of $\$$5/lb to $\$$50/lb, respectively. Moreover, the site case study suggests that the coal tar from the single integrated steel mill could supply production of up to 16 kt/yr of carbon fiber. Finally, a technological gap analysis was done which shed light on remaining technical challenges. These challenges included: recovery and utilization of condensates from the mesophase pitch processing, further advancing and increasing stability of the multifilament melt spinning processing, optimization of the oxidation processing, defect reduction for increased carbon fiber strength, and the development of a weaving process towards carbon fiber fabrics. To maximize the coal value chain, the primary objectives of this project were to (a) develop and scale efficient processing technology for producing melt-spinnable mesophase pitch from isotropic coal tar pitch, (b) clarify and simplify tedious continuous fiber processing technologies (particularly multifilament melt spinning of mesophase pitch) towards the efficient production of high performance carbon fiber, and (c) demonstrate and characterize representative composite parts derived from the final carbon fiber. Immense progress was made on all 3 objectives and is detailed in this report.
01 COAL, LIGNITE, AND PEAT↗
Ceramic materials purified by experimental method
Crystalline ceramic materials are purified for use as high-temperature electrical insulators. Any impurities migrate to the cathode when a dc voltage is applied across the material while it is heated in an inert gas atmosphere.
Source record↗
Tungsten wire and tubing joined by nickel brazing
Thin tungsten wire and tungsten tubing are brazed together using a contacting coil of nickel wire heated to its melting point in an inert-gas atmosphere. This method is also effective for brazing tungsten to tungsten-rhenium parts.
Source record↗
Split glass tube assures quality in electron beam brazing
Sealed enclosure of heat-resistant glass tubing and silicone rubber molds provide good visibility for electron beam brazing of metal tubes in an inert gas atmosphere. The glass tubing and rubber molds, which are bonded together, are easily applied to and removed from the brazing area by operation of a clamp.
Kressin, W. J.↗
Brazing process using'al-Si filler alloy reliably bonds aluminum parts
Brazing process employs an aluminum-silicon filler alloy for diffusion bonding of aluminum parts in a vacuum or inert gas atmosphere. This process is carried out at temperatures substantially below those required in conventional process and produces bonds of greater strength and reliability.
Beuyukian, C. S.↗
Process for preparing dispersions of alkali metals
Finely divided particles of alkali metals are produced by combining alkali metals with certain aromatic compounds in selected solvents to form low-temperature soluble complexes from which the pure alkali metals precipitate quantitatively when the solutions are warmed. All operations must be carried out in an inert gas atmosphere.
Landel, R. F.↗
Relative Decompression Risks of Spacecraft Cabin Atmospheres - Comparision of Gases Using Miniature Pigs Final Report
Using miniature pigs for analysis of altitude decompression sickness and relative decompression hazards of various cabin atmospheres of inert gases
Doebbler, G. F.↗
High-Temperature, Low-Cycle Fatigue Behavior of Tantalum
High temperature, low cycle fatigue tests of tantalum in inert argon atmosphere
LaForce, R.↗
Deposition of alloy films
An invention is described which deposits metal alloy films on a metal object. A glow discharge is established by applying a high voltage between an anode and a cathode object disposed in an inert gas atmosphere. An alloy of two or more metals is vaporized and the vapor injected into the glow discharge causing the alloy to be plated onto the cathode object.
Spalvins, T.↗
Preparation of thick molybdenum targets
Thick natural molybdenum deposits on nickel plated copper substrates were prepared by thermal decomposition of molybdenum hexacarbonyl vapors on a heated surface in an inert gas atmosphere. The molybdenum metal atoms are firmly bonded to the substrate atoms, thus providing an excellent thermal contact across the junction. Molybdenum targets thus prepared should be useful for internal bombardment in a cyclotron where thermal energy inputs can exceed 10 kW.
Singh, J. J.↗
Recharging the Silicon Crucible in a Hot Furnace
"Melt recharger" adds raw silicon to crucible in crystal-growing furnace without disturbing inert-gas atmosphere or significantly lowering temperature of melt. Crucible-refill hopper is lowered into hot zone of crystal-pulling chamber through an isolation valve. Cable that supports hopper is fastened to cone-shaped stopper in bottom of hopper. Stopper moves out of opening in hopper, allowing part of polysilicon charge to drop into crucible.
Lane, R. L.↗
Fluxless Brazing of Large Structural Panels
Fluxless brazing is used in fabricating aluminum structural panels that withstand high internal pressure. Aluminum sheet of structural thickness with 4045 aluminum/silicon-braze-alloy cladding is brazed to corrugated "fin stock" having channels 0.001 inch (0.03mm) high by same width. Process is carried out in an inert (argon) atmosphere in a retort furnace. Filler bars are used in some channels to prevent fin stock from collapsing as pressure is applied.
Beuyukian, C. S.↗
Molten salt pyrolysis of latex
Latex-rich plants such as Guayule or extracts thereof are pyrolyzed in an inert nitrogen atmosphere inorganic salt melts such as a LiCl/KCl eutectic at a temperature of about 500 C. The yield is over 60% of a highly aromatic, combustible hydrocarbon oil suitable for use as a synthetic liquid fuel.
Bauman, A. J.↗
Spacecraft Fire Safety
Fire detection, fire standards and testing, fire extinguishment, inerting and atmospheres, fire-related medical science, aircraft fire safety, Space Station safety concerns, microgravity combustion, spacecraft material flammability testing, and metal combustion are among the topics considered.
Margle, Janice M.↗
Crystal Furnace
A "melt recharging" technique which eliminates the cooldown and heating periods in a crystal "growing" crucible, resulted from a Jet Propulsion Laboratory (JPL)/Kayex Corporation program. Previously, the cost of growing the silicon solar cells had been very high. The JPL/Kayex system improved productivity by serially growing crystals from the same crucible using a melt recharger which made it possible to add raw silicon to an operating crucible. An isolation value, developed by Kayex, allowed the hopper to be lowered into the crucible without disturbing the inert gas atmosphere. The resulting product, a CG6000 crystal growing furnace, has become the company's major product.
Source record↗
Chemochromic detector for sensing gas leakage and process for producing the same
A chemochromic sensor for detecting a combustible gas, such as hydrogen, includes a chemochromic pigment mechanically mixed with a polymer and formed into a rigid or pliable material. In a preferred embodiment, the chemochromic detector includes aerogel material. The detector is robust and easily modifiable for a variety of applications and environmental conditions, such as atmospheres of inert gas, hydrogen gas, or mixtures of gases, or in environments that have variable temperature, including high temperatures such as above 100.degree. C. and low temperatures such as below -196.degree. C.
Roberson, Luke B.↗
Chemochromic Detector for Sensing Gas Leakage and Process for Producing the Same
A chemochromic sensor for detecting a combustible gas, such as hydrogen, includes a chemochromic pigment mechanically mixed with a polymer and molded into a rigid or pliable shape. In a preferred embodiment, the chemochromic detector is within the material which is molded into a manufactured part, said part becoming the detector itself. The detector is robust and easily modifiable for a variety of applications and environmental conditions, such as atmospheres of inert gas, hydrogen gas, or mixtures of gases, or in environments that have variable temperature, including high temperatures such as above 100 C. and low temperatures such as below -196 C.
Roberson, Luke B.↗