Manufacturing & Prototyping

Advanced Composite Thrust Chambers for In-Space Propulsion

Marshall Space Flight Center, Alabama Radiation-cooled, bipropellant thrust chambers are being used for in-space propulsion. To increase the performance of radiation-cooled engines, improved chamber materials are needed that will allow higher operating conditions (pressure and temperature), better resistance to oxidation, and reduced mass. During this effort, an innovative composite thrust chamber is being developed that will incorporate advanced hafnium oxide and iridium liner techniques as well as replacing the expensive, high-density rhenium with a low-mass carbon-carbon (C–C) structural wall.

Posted in: Manufacturing & Prototyping, Briefs

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Integrally Woven Fiber Architecture for Composite Turbine Blades

John H. Glenn Research Center, Cleveland, Ohio Composite turbine blades are currently fabricated by laying up multiple layers of fibers in the form of either unidirectional prepregs or thin woven cloth. Composites formed in this manner have poor through-thickness strength. It is also difficult, if not impossible, to form trailing edges as thin as necessary for optimum engine performance.

Posted in: Manufacturing & Prototyping, Briefs, TSP

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Assembly and Packaging to Mass-Produce Carbon Nanotube Vacuum Microdevices and Circuits

An assembly process allows mixing and matching of different types of electrode and dielectric layers assembled in a stack to create multi-electrode vacuum devices. NASA’s Jet Propulsion Laboratory, Pasadena, California Field-emission electron sources using carbon nanotubes (CNTs) are being targeted for low-power vacuum microelectronic applications for harsh-environment operation (high temperature, pressure, and corrosive atmosphere). While CNTs have demonstrated excellent properties in terms of low threshold field, low-power operation, and high-current densities, one of the problems that has persisted for vacuum electronic applications is the low yield of multi-electrode vacuum devices such as diodes, triodes, tetrodes, pentodes, etc.

Posted in: Manufacturing & Prototyping, Briefs, TSP

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The Final Step In Prototyping: Enhancing Your Metal Parts For Accelerated Speed To Market

Electropolishing is often referred to as a “reverse plating” process. Electrochemical in nature, electropolishing uses a combination of rectified current and a blended chemical electrolyte bath to remove flaws from the surface of a metal part.

Posted in: Manufacturing & Prototyping, White Papers

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Engineers Use Resin Inks, 3D Printing to Build Lightweight Cellular Composites

Like other manufactured products that use sandwich panel construction to achieve a combination of light weight and strength, turbine blades contain carefully arrayed strips of balsa wood from Ecuador, which provides 95 percent of the world’s supply.As turbine makers produce ever-larger blades—the longest now measure 75 meters, almost matching the wingspan of an Airbus A380 jetliner—they must be engineered to operate virtually maintenance-free for decades. In order to meet more demanding specifications for precision, weight, and quality consistency, manufacturers are searching for new sandwich construction material options.Now, using a cocktail of fiber-reinforced epoxy-based thermosetting resins and 3D extrusion printing techniques, materials scientists at the Harvard School of Engineering and Applied Sciences (SEAS) and the Wyss Institute for Biologically Inspired Engineering have developed lightweight cellular composite materials.The work could have applications in many fields, including the automotive industry where lighter materials hold the key to achieving aggressive government-mandated fuel economy standards. SourceAlso: See more Materials tech briefs.

Posted in: Manufacturing & Prototyping, Rapid Prototyping & Tooling, Materials, Composites, Aerospace, Aviation, News

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Full-Cell Evaluation/Screening Technique for New Battery Chemistries

A full-cell configuration with a limited electrolyte in the cell is used to reflect the actual cell build conditions. John H. Glenn Research Center, Cleveland, Ohio A quick and cost-effective evaluation/screening technique for new battery chemistries was developed that integrates the individual advanced cell component in a full-cell format to identify the critical issues, such as cell component interaction and compatibility before proceeding to commercial production. To make the assessment more practical, a unique way of introducing limited electrolyte was developed. This technique enabled fast and low-cost screening to address any potential issues.

Posted in: Manufacturing & Prototyping, Briefs, TSP

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Growth Method for Chalcongenide Phase-Change Nanostructures

Nanometer-scale materials can provide smaller devices than those currently available. Ames Research Center, Moffett Field, California Recently, one-dimensional (1-D) nanostructures, such as nanowires and nanotubes, have become the focal point of research in nanotechnology due to their fascinating properties. These properties are intrinsically associated with low dimensionality and small diameters, which may lead to unique applications in various nanoscale devices. It is generally accepted that 1-D nanostructures provide an excellent test ground for understanding the dependence of physical, electrical, thermal, optical, and mechanical properties on material dimensionality and physical size. In particular, 1-D semiconductor nanostructures, which exhibit different properties as compared with their bulk or thin film counterparts, have shown great potential in future nanoelectronics applications in data storage, computing, and sensing devices.

Posted in: Manufacturing & Prototyping, Briefs

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