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Results for “electrode processing”

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 NTRS1982

Positive electrode processing for Hughes NiH2 cells

The basic procedures were developed for the manufacture of nickel cadmium batteries. An electrochemical impregnation in an aqueous ethanol solution is used in this process. Several additional controls were instituted for production of flight electrodes, including a Hughes controlled MCD, a solution reserved exclusively for the impregnation of Hughes positive electrodes a system of complete traceability for individual electrodes, an electrical characterization test to provide information on weight and capacity at the plaque level, and a stress test to provide data on capacity, weight, and physical parameters at the electrode level.

Bleser, C. A.↗
NASA NTRS1997

Performance Comparison Between NiH2 Dry Sinter and Slurry Electrode Cells

The electrical and thermal performance of dry sinter and slurry process electrode cells manufactured for the Hubble Space Telescope (HST) batteries have been characterized for a matrix of operating conditions over the temperature range from 14 to 86 F at various charge control levels. The dry sinter process electrode cells tested are similar to the onboard HST NiH2 cells. The slurry process electrode cells were developed to be less susceptible to electrode expansion and impedance changes with life. Both cell types were impregnated by the aqueous electrochemical process. Test conditions included standard capacity tests and electrical cycling using 96-minute cycling regimens incorporating gr depth-of-discharge (DOD) cycles. The dry sinter process electrodes have higher operating capacities to 1.20V/cell, but both electrode types have similar heat dissipation for the conditions tested. The results of the testing included cyclic heat generation during a typical 96-minute cycle, operating capacity data vs. cutoff voltage to generate a temperature-compensated voltage curve, and voltage characteristics suitable to develop a voltage prediction model. Analysis of data shows differences in the discharge voltage plateaus operating conditions evaluated. This is the basis for recommended changes in the battery charge control.

Armantrout, J. D.↗
NASA NTRS1970

Properties of Hot Pressed Titanium Alloy Powders for Cryogenic Applications.

Evaluation of strength and toughness of hot-pressed titanium alloy powders at room and at cryogenic temperatures. The purpose was to determine how the mechanical properties of solid bodies formed from powder would compare with wrought specimens of the same size and with the same chemical analysis. It was found that of five titanium powder-making processes investigated, only the Rotating Electrode Process (REP) was capable of producing ELI-grade titanium alloy powder. Blocks hot-pressed from spherical REP powders had tensile properties equivalent to or better than those obtained from wrought bar.

Friedman, G. I.↗
NASA NTRS1987

Na/beta-alumina/NaAlCl4, Cl2/C circulating cell

A study was made of a high specific energy battery based on a sodium negative electrode and a chlorine positive electrode with molten AlCl3-NaCl electrolyte and a solid beta alumina separator. The basic performance of a Na beta-alumina NaAlCl4, Cl2/C circulating cell at 200 C was demonstrated. This cell can be started at 150 C. The use of melting sodium chloroaluminate electrolyte overcomes some of the material problems associated with the high working temperatures of present molten salt systems, such as Na/S and LiAl/FeS, and retains the advantages of high energy density and relatively efficient electrode processes. Preliminary investigations were conducted on a sodium-chlorine static cell, material compability, electrode design, wetting, and theoretical calculations to assure a better chance of success before assembling a Na/Cl2 circulating cell. Mathematical models provide a theoretical explanation for the performance of the NaCl2 battery. The results of mathematical models match the experimental results very well. According to the result of the mathematical modeling, an output at 180 mA/sq cm and 3.2 V can be obtained with optimized cell design.

Cherng, Jing-Yih↗
NASA NTRS1967

Electrochemical engineering

Overpotential transients on rotating disk, current and potential distributions in cylinders, foamed electrolyte fuel cell, atomic scale electrode processes, and charge transfer complexes

Bockris, J. O.↗
NASA NTRS1987

Advances in nickel hydrogen technology at Yardney Battery Division

The current major activites in nickel hydrogen technology being addressed at Yardney Battery Division are outlined. Five basic topics are covered: an update on life cycle testing of ManTech 50 AH NiH2 cells in the LEO regime; an overview of the Air Force/industry briefing; nickel electrode process upgrading; 4.5 inch cell development; and bipolar NiH2 battery development.

Bentley, J. G.↗
NASA NTRS1988

Microstructures in rapidly solidified niobium aluminides

The microstructures of niobium aluminides produced by chill block melt spinning were compared to those of niobium aluminides produced by conventional casting. The rapidly solidified alloys were rapidly solidified by melt spinning in an argon atmosphere, and the melt-spun ribbons were examined by optical, X-ray, and TEM techniques. Microstructures were found to range from single-phase for Nb-75 at. pct Al (NbAl3) to two phase for Nb-46 at. pct Al (NbAl3 + Nb2Al). It was found that the melt spinning of Nb-aluminides produced finer grained microstructures than those produced in induction-melted ingots or in powders produced by the rotating electrode process. Ternary additions such as Cr, Ti, and Si tended to form intermetallic phases along the grain boundaries.

Hebsur, Mohan G.↗
NASA NTRS1991

MPD thruster technology

MPD (MagnetoPlasmaDynamic) thrusters demonstrated between 2000 and 7000 seconds specific impulse at efficiencies approaching 40 percent, and were operated continuously at power levels over 500 kW. These demonstrated capabilities, combined with the simplicity and robustness of the thruster, make them attractive candidates for application to both unmanned and manned orbit raising, lunar, and planetary missions. To date, however, only a limited number of thruster configurations, propellants, and operating conditions were studied. The present status of MPD research is reviewed, including developments in the measured performance levels and electrode erosion rates. Theoretical studies of the thruster dynamics are also described. Significant progress was made in establishing empirical scaling laws, performance and lifetime limitations and in the development of numerical codes to simulate the flow field and electrode processes.

Myers, Roger M.↗
NASA NTRS1991

MPD thruster technology

MPD thrusters have demonstrated between 2000 and 7000 sec specific impulse at efficiencies approaching 40 percent, and have been operated continuously at power levels over 500 kW. These demonstrated capabilities, combined with the simplicity and robustness of the thruster, make them attractive candidates for application to both unmanned and manned orbit raising, lunar, and planetary missions. This work reviews the present status of MPD thruster research, including developments in the measured performance levels and electrode erosion rates, and theoretical studies of the thruster dynamics. Significant progress has been made in establishing empirical scaling laws, performance and lifetime limitations, and in the development of numerical codes to simulate the flowfield and the electrode processes.

Myers, Roger M.↗
NASA NTRS1992

Chronopotentiometry of refractory metals, actinides and oxyanions in molten salts: A review

The applications of chronopotentiometry to the study of electrochemical behavior of three technologically important areas of refractory metals, actinides, and oxyanions in molten salts are critically reviewed. Chronopotentiometry is a very versatile diagnostic tool to understand the reaction mechanism of the electrode processes for the electrochemical reduction/oxidation of these electroactive species in molten salt solutions. Well adherent, compact, and uniformly thick coatings of refractory metals may be electrodeposited from their solutions in molten salts.

Bansal, Narottam P.↗
NASA NTRS1994

Advanced silver zinc battery development for the SRB and ET range safety subsystems

This document presents in viewgraph format the design and development of silver zinc (AgZn) batteries for the solid rocket booster (SRB) and external tank (ET) range safety subsystems. Various engineering techniques, including composite separator systems, new electrode processing techniques, and new restraint techniques, were used to meet difficult requirements.

Adamedes, Zoe↗
NASA NTRS2002

NiH2 Cycle Life Study

Cycle life studies have been performed at Eagle Picher Technologies (EPT), on HST Mantech design cells with various pedigrees of slurry and dry sinter processed electrodes, to evaluate peak load voltage performance during generic load profile testing. These tests provide information for determining voltage and capacity fade (degradation) mechanisms, and their impact on nickel hydrogen cell cycle life. Comparison of peak load voltage fade, as a function of State of Charge and cycle life, with capacity data from HST indicates that the cycle life limiting mechanism is due to impedance growth, and formation of a second discharge plateau. With a second plateau on discharge, capacity from the cell is still available, but at an unacceptable low voltage of 0.8 V per cell (17.6 V battery). Data shows that cell impedance increases with cycle number and depth of discharge, as expected.

Hollandsworth, Roger P.↗
NASA NTRS2006

Hubble Space Telescope 2004 Battery Update

Battery cell wear out mechanisms and signatures are examined and compared to orbital data from the six on-orbit Hubble Space Telescope (HST) batteries, and the Flight Spare Battery (FSB) Test Bed at Marshall Space Flight Center (MSFC), which is instrumented with individual cell voltage monitoring. The on-orbit HST batteries were manufactured on an expedited basis after the Challenger Shuttle Disaster in 1986. The original design called for the HST to be powered by six 50 Ah Nickel Cadmium batteries, which would have required a shuttle mission every 5 years for battery replacement. The decision to use NiH2 instead has resulted in a longer life battery set which was launched with HST in April 1990, with a design life of 7 years that has now exceeded 14+ years of orbital cycling. This chart details the specifics of the original HST NiH2 cell design. The HST replacement batteries for Service Mission 4, originally scheduled for Spring 2005, are currently in cold storage at NASA Goddard Space Flight Center (GSFC). The SM4 battery cells utilize slurry process electrodes having 80% porosity.

Hollandsworth, Roger↗
NASA NTRS1989

Nickel-hydrogen capacity loss on storage

A controlled experiment evaluating the capacity loss experienced by nickel electrodes stored under various conditions of temperature, hydrogen pressure, and electrolyte concentration was conducted using nickel electrodes from four different manufacturers. It was found that capacity loss varied with respect to hydrogen pressure, and storage temperature as well as with respect to electrode manufacturing processes. Impedance characteristics were monitored and found to be indicative of electrode manufacturing processes and capacity loss. Cell testing to evaluate state-of-charge effects on capacity loss were inconclusive as no loss was sustained by the cells tested in this experiment.

Manzo, Michelle A.↗
NASA NTRS1990

Nickel-hydrogen capacity loss on storage

A controlled experiment evaluating the capacity loss experienced by nickel electrodes stored under various conditions of temperature, hydrogen pressure, and electrolyte concentration was conducted using nickel electrodes from four different manufacturers. It was found that capacity loss varied with regard to hydrogen pressure and storage temperature, as well as with regard to electrode manufacturing processes. Impedance characteristics were monitored and found to be indicative of electrode manufacturing processes and capacity loss. Cell testing to evaluate state-of-charge effects on capacity loss were inconclusive as no loss was sustained by the cells tested in this experiment.

Manzo, Michelle A.↗
NASA NTRS1999

Enhanced vacuum arc vapor deposition electrode

A process for forming a thin metal coating on a substrate wherein a gas stream heated by an electrical current impinges on a metallic target in a vacuum chamber to form a molten pool of the metal and then vaporize a portion of the pool, with the source of the heated gas stream being on one side of the target and the substrate being on the other side of the target such that most of the metallic vapor from the target is directed at the substrate.

Weeks, Jack L.↗