Materials

Alloys

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Briefs: Materials
Diffusing Hf and Si Into Aluminide Bond Coats for TBCs
A process for making superior diffusion platinum-aluminide bond coats for plasma-sprayed or physical-vapor-deposited thermal-barrier coats (TBCs) on superalloy substrates has been devised. The novel aspect of the process lies in the use of several relatively inexpensive pack diffusion steps to...
Briefs: Materials
A process that involves reaction bonding makes it possible to form strong joints, with tailorable thicknesses and compositions, between high-temperature-resistant structural parts...
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Briefs: Materials
Nonchromic Acid Brightener for Brass and Copper
A process for precleaning brass and copper parts before processing them further in a clean room includes a brightening chemical treatment in solution of 85 volume percent phosphoric acid, 3 volume percent nitric acid, and 12 volume percent acetic acid. This solution acts rapidly and can be discarded...
Briefs: Materials
Zn4Sb3 has been identified as a high-performance thermoelectric material. In p-type, Zn4Sb3 samples have exhibited the greatest dimensionless thermoelectric figure of merit ever observed...
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Briefs: Materials
An alloy of 88Cu/8Cr/4Nb (numbers indicate atomic percentages) has been proposed for use in fabricating rocket-engine combustion chambers by vacuum plasma spraying (VPS). Relative to...
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Briefs: Photonics/Optics
Computer Code for Analysis of Stress in Silicon Wafers
The MacWafer™ code computes gravitational and thermal stresses in silicon wafers and uses these results to determine the maximum allowable temperature variation across a wafer, maximum processing temperatures, and maximum allowable heating and cooling rates. This information is of particular...
Briefs: Manufacturing & Prototyping
A process for the fabrication of improved high-temperature fiber-optic sensor heads has been proposed. Fiber-optic sensor heads that can withstand hot, dirty, noisy environments are...
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Briefs: Robotics, Automation & Control
Zinc telluride is a semiconductive material that has been found to become photorefractive when it is suitably doped with vanadium or with manganese and vanadium. The combination of...
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Briefs: Materials
Experiments have shown that improved hydride-forming negative electrodes for rechargeable nickel/metal hydride (Ni/MH) electrochemical cells can be made by substituting Sn for some...
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Briefs: Materials
A modified alloy, known as Modified PWA1484, is a single-crystal nickel-base superalloy, developed under a NASA Marshall Space Flight Center contract for use as a turbine blade and vane alloy for the...
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Briefs: Electronics & Computers
The figure illustrates a dc-excited Anderson-loop circuit that includes (1) thermocouples for measuring the temperature of the strain gauge and (2) a signal-conditioning circuit that...
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Briefs: Electronics & Computers
Due to their low density and exceptionally high strength and modulus, graphite fiber composites are being used increasingly for the fabrication of aircraft and spacecraft. Because of their superior...
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Briefs: Materials
Engineers at Rockwell International Corporation's Space System Division have developed a new method of insulating composite structural material...
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Briefs: Materials
A process that involves reaction forming has been devised to enable the joining of high-temperature-resistant structural parts made of SiC-based materials. These materials...
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Briefs: Electronics & Computers
Fabrication of Arrays of Large Step-Free Regions on Si(100)
When a silicon wafer is cut from an ingot, it is essentially impossible to align the cut perfectly with the crystal structure. Therefore the surface contour of the wafer will be a flat plane on which terraces consisting of additional atomic layers will be scattered. An atomic step will be...
Briefs: Materials
Experiments have shown that carbon-based materials containing pure metallic iron, alloys of iron, halides of iron, and/or oxides of iron can be synthesized from precursors of general...
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Briefs: Manufacturing & Prototyping
Processes for fabricating thin-film type-S thermocouples on metal and silicon nitride substrates (see figure) have been developed. (A type-S thermocouple comprises one leg made of platinum and the...
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Briefs: Materials
The figure illustrates one of several related pin-puller mechanisms that harness the recovery characteristics of a shape-memory alloy (SMA). Like some other SMA-actuated mechanisms...
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Briefs: Materials
Phospha-s-Triazines and Other Compounds for Use as Additives
A report describes research on selected compounds as additives to perfluoroalkyether (PFPAE) fluids that are used as synthetic lubricants for metal parts. Additives are needed to inhibit both thermo-oxidative degradation of, and corrosion of metals by, the PFPAE fluids in the presence of...
Briefs: Motion Control
Permanent-magnet rotary bearings with ferrofluid stabilization in the axial degree of freedom are undergoing development. These bearings are totally passive, yet stable in all degrees of...
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Briefs: Motion Control
The latest missile guidance and tracking guidance systems deliver unprecedented performance, in terms of range, precision, and the ability to function in very unfavorable atmospheric conditions....
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Briefs: Manufacturing & Prototyping
A friction stir weld (FSW) system for welding and weld repair can be used on the manufacturing floor, as well as in the laboratory environment. This FSW system can be used in a wide variety...
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