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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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We have investigated visible photoluminescence from thin porous ally layers perpared by stain etching from the molecular beam epitaxy grown material.
Accurate quantification of combustor pressure dynamics for the primary purpose of experimental validation of computational fluid dynamics (CFD) codes requires the use of robust, reliable and sensitive pressure sensors that can resolve sub--pound-per-square-inch pressure levels in high temperature environments (i.e., combustor). The state of the art microfabricated piezoresistive silicon carbide (SiC) pressure sensors that we have developed are capable of operating reliably at 600 degrees Centigrade. This technology was used in support of the ARMD ISRP-ERA (NASA's Aeronautics Research Mission Directorate, Integrated System Research Project - Environmentally Responsible Aviation) program to quantify combustor thermoacoustic instabilities. The results showed that while the SiC pressure sensors survived the high temperature and measured instabilities, the diaphragm (force collector) was not thin enough to be sensitive in resolving sub-pound-per-square-inch pressures; 30 meters is the thinnest diaphragm achievable with conventional reactive ion etching (RIE) processes. Therefore, this precludes its use for sub-pound-per-square-inch pressure measurement with high fidelity. In order to effectively resolve sub-pound-per-square-inch pressures, a thinner more sensitive diaphragm (10 meters) is needed. To achieve this would require a new and innovative fabrication process technique.
Electroless nickel resist is unaffected by caustic soda applied as a milling or etching agent on aluminum.
Electrolytic etching process prepares surfaces of a stainless steel shell for reliable, high strength adhesive bonding to dielectric materials. The process uses a 25 percent aqueous solution of phosphoric acid.
Four step photoresist process for etching thick aluminum layers for semiconductor device contacts produces uniform contact surfaces, eliminates bridging, minimizes undercutting, and may be used on various materials of any thickness.
Nucleate boiling heat transfer from mechanically polished, chemically etched stainless steel boiling plate
Etch-decoration technique of detecting vacancies in graphite has been used to determine the reaction rates of graphite with ozone in the directions parallel and perpendicular to the layer planes. It consists essentially of peeling single atom layers off graphite crystals without affecting the remainder of the crystal.
Cylindrical diodes with etched Re emitters, testing output power variation with voltage and efficiency variation over lifetime
Pool boiling data at atmospheric pressure for mechanically polished and chemically etched 304 stainless steel surfaces in contact with distilled water
Thermionic converter with fluorine vapor deposited tungsten emitter etched to expose crystal planes
Thin foil preparation technique for transmission electron microscopy and selected etch pitting technique for CoO single crystals
Germanium single crystals etching with water vapor and hydrogen sulfide in hydrogen flow system, studying concentration, pressure and temperature effects on surface reactions
Computer acquired performance map of etched-rhenium, niobium planar diode
Vibratory cavitation for metal and superalloy etching in distilled water
Etching aluminum alloys with aqueous solution containing sulfuric acid, hydrofluoric acid, and an alkali metal dischromate for adhesive bonding
Selective plating of etched circuits without removing previous plating
Computer processed performance data for thermionic converter with etched rhenium emitter and niobium collector