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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 217 records · Page 12

A versatile silver oxide-zinc battery for synchronous orbit and planetary missions

A new kind of silver-zinc cell was developed and tested under NASA support which can withstand severe heat sterilization requirements and does not display the traditional life limiting aspect of sinc electrodes i.e. shape change. These cells could be used on planetary lander mission which require wet-stand periods of over a year, a modest number of cycles (400 to 500) and may require dry heat sterilization. The weight advantage of these cells over the traditional nickel cadmium batteries also makes it an attractive alternative for synchronous orbit service where 400 to 500 cycles would be required over a 5 year period.

Schwartz, H. J.↗

Evaluation program for secondary spacecraft cells: Acceptance test of McDonnell-Douglas, Astropower division, 40.0 ampere hour silver-zinc cells

The development of an inorganic separator material for use in construction of 40 ampere-hour silver zinc cells is discussed. Acceptance tests were conducted to determine real quality, physical defects and ampere-hour capacity. All acceptance tests were performed at an ambient temperature of 23 to 27 C at existing relative humidity and atmospheric pressure. Of the 63 cells tested, only one failed to meet the equipment specifications.

Harkness, J. D.↗

Investigation of solid state electrolyte silver-zinc battery

Study of the solid electrolyte ZnCl2-2NH3 rechargeable silver zinc electrochemical cell by X-ray diffraction analysis of the reaction products led to the conclusion that some water is consumed when the cell is discharged. Replacement of ZnCl2-2NH3 by ZnCl2-4Zn(OH)2 gave cells with high internal resistance and limited capacity. The salt formed by exposing a fibrous membrane saturated with ZnCl2 solution to fumes from ammonium carbonate in a dry desiccator comprised ZnCl2-4Zn(OH)2, ZnCl2,3NH4Cl and a third unidentified component. The temperature coefficient of open circuit EMF was nearly zero over the range from -25 C to 50 C. The internal resistance and polarization increased substantially below -25 C. There is some indication that exposure to 50 C for 29 hours causes some deterioration.

Source record↗

Automatically activated, 300 ampere-hour silver-zinc cell

A prototype silver zinc cell is reported for which the electrolyte is being stored in a separate tank; the cell is being activated when additional power is required by collapsing the neoprene bellows container and thus forcing the electrolyte into cell through a plastic connection. A solar array is proposed as main power source for the flow actuator.

Hennigan, T. J.↗

Lifetime estimates for sterilizable silver-zinc battery separators

The lifetime of separator membranes currently employed in the electrolyte environment of silver-zinc batteries was estimated at 3 to 5 years. The separator membranes are crosslinked polyethylene film containing grafted poly (potassium acrylate)(PKA), the latter being the hydrophilic agent which promotes electrolyte ion transport. The lifetime was estimated by monitoring the rate of loss of PKA from the separators, caused by chemical attack of the electrolyte, and relating this loss rate to a known relationship between battery performance and PKA concentration in the separators.

Cuddihy, E. F.↗

Photoemission studies of wurtzite zinc oxide.

The electronic structure of wurtzite zinc oxide, investigated over the widest possible photon energy range by means of photoemission techniques, is described. Of particular interest among the results of the photoemission study are the location of the Zn 3rd core states, the width of the upper valence bands, and structure in the conduction-band and valence-band density of states.

Powell, R. A.↗

An improved technique for the use of zinc-rich coatings

Blistering and peeling of topcoats used over ethyl silicate, inorganic, zinc-rich protective coatings are virtually eliminated when primer is allowed to cure outdoors for extended period of time and is moistened during process.

Paton, W. J.↗

The electrical properties of 60 keV zinc ions implanted into semi-insulating gallium arsenide

The electrical behavior of zinc ions implanted into chromium-doped semiinsulating gallium arsenide was investigated by measurements of the sheet resistivity and Hall effect. Room temperature implantations were performed using fluence values from 10 to the 12th to 10 to the 15th power/sq cm at 60 keV. The samples were annealed for 30 minutes in a nitrogen atmosphere up to 800 C in steps of 200 C and the effect of this annealing on the Hall effect and sheet resistivity was studied at room temperature using the Van der Pauw technique. The temperature dependence of sheet resistivity and mobility was measured from liquid nitrogen temperature to room temperature. Finally, a measurement of the implanted profile was obtained using a layer removal technique combined with the Hall effect and sheet resistivity measurements.

Littlejohn, M. A.↗