Researchers at NASA’s Glenn Research Center have patented a self-lubricating, friction- and wear-reducing composite material useful over a wide temperature range, from cryogenic temperatures (-185°C) to about 900°C. This composite, which is composed of chromic oxide in a metal binder along with metal fluoride and an optional metal lubricant, is less abrasive and more resistant to oxidation than composites containing chromium carbide. The chromic oxide component of the composite provides hardness, wear resistance, and thermal stability, and exhibits low friction when used in sliding contacts. The composite is readily applied using plasma spray and can be ground and polished with a silicon carbide abrasive.

NASA Glenn Research Center (GRC) seeks to transfer technology for further development and production of its polymer cross-linked aerogels (X-Aerogels). These mechanically robust, highly porous, low-density materials are 3 times denser than native aerogels, but more than 100 times stronger.

Scientists at the NASA’s Glenn Research Center have developed an electrolyte material that enables solid polymer lithium batteries to operate at room temperature. Solid polymer lithium batteries offer many advantages over other battery designs. In particular, Glenn has demonstrated significant improvements in ionic conductivity and mechanical integrity, both of which are important for battery and fuel cell applications.

NASA’s Glenn Research Center has enhanced its process for developing polymer cross-linked aerogels (X-Aerogels). Glenn previously was able to increase the strength without adversely affecting the porosity or low density by cross-linking silica and other oxide aerogels with a polymeric material. However, these aerogels still were subject to brittle failure. The improved process now provides flexible linking groups as part of the monolith structure, boosting the strength, elasticity, and resiliency of the aerogel.

Researchers at NASA’s Glenn Research Center have patented a process for producing metal or metal oxides for distribution within a porous carbon substrate. This process emphasizes compound production where graphite oxide is used as an origin material. The graphite oxide is exposed to metal chlorides at or below the thermal decomposition temperature of the graphite oxide for a time sufficient to obtain an intermediary carbonaceous reaction product comprising metal, oxygen, and chlorine. Further processing can produce metal oxide, metal oxide on carbon, or elemental metal in the shape of the carbon precursor.

Innovators at NASA’s Glenn Research Center have patented an improved thermal barrier coating that provides enhanced thermal fatigue life through modification of the bond coat coefficient of thermal expansion in targeted regions of the bond coat microstructure. Designed for use with a high temperature substrate, the coating includes two bond coat layers, both of which are comprised of MCrAlX, where M is nickel, cobalt, or iron and X is a reactive element such as yttrium, zirconium, hafnium, or ytterbium. The second bond coat layer includes particulates such as alumina that are evenly and finely dispersed throughout the MCrAIX matrix. The first bond coat is applied to the substrate, and the second bond coat layer is applied over the first. This method produces thin thermal barrier coatings with higher thermal fatigue resistance than traditional thin coatings and avoids the added weight associated with conventional thick multi-layer graded coatings. This design also avoids the disadvantage of isolated areas of MCrAIX in thick graded coatings. By ensuring an even distribution of particles in the second bond coat layer, this method produces robust, thin thermal barrier coatings and overcomes disadvantages of prior thin and thick coating methods.

Researchers at NASA’s Glenn Research Center have patented a unique shape-memory alloy (SMA) microactuator where hot gas or optical energy is employed to activate a shape-memory alloy, eliminating the need for electrical energy to power the operation. In the hot gas embodiment, the flow of hot gas to the SMA elements is preferably controlled by optically operated switches. In the optical energy embodiment, optical energy such as laser energy may be applied directly to SMA elements using optical energy transmission. The SMA microactuator is particularly suitable for gas turbine-powered aircraft where a ready and abundant supply of high-temperature gas is available from the compressor or turbine section of the gas turbine engine.

Researchers at NASA’s Glenn Research Center have patented a macro-segmented thermal barrier coating. Thermal barrier coatings protect component substrates that are subjected to high-temperature operations. The thermal barrier coating system generally includes a ceramic layer for thermal insulation and an additional layer, called a bond coat, located between the substrate and ceramic layer. The bond coat typically serves to increase adherence of the ceramic layer on the metallic substrate and protect the underlying substrate from oxidation. When the substrate is subjected to repeated heating and cooling, thermally induced stresses are produced and accumulate within the thermal barrier coating system. This enhanced thermal barrier coating system uses 3-D features, such as ribs or grooves, on the substrate or bond coat to provide increased resistance to spallation. It also extends the life of a coated component after spallation by preventing crack growth.

Researchers at NASA’s Glenn Research Center have patented a method for synthesizing addition-cured thermosetting polyimides (PMR-type) with the incorporation of an aromatic triamine core and reactive end caps. Unlike linear polyimides, these star-branched polyimides exhibit a higher glass transition temperature, increased thermo-oxidative stability, and a lower melt-flow viscosity that make for relatively easy and inexpensive processing and molding.
The improved ease of processing the new GRC polyimides, along with thermosetting polyimides’ high-temperature capabilities, make them attractive for use as high-performance matrix resins in lightweight, structurally efficient fiber-reinforced polymer matrix composites. Such polymer matrix composites are increasingly used in the electronics, automotive, and aerospace industries.
 

Researchers at NASA’s Glenn Research Center have patented a unique process called “photochemical cyclopolymerization” that employs energy from ultraviolet light (rather than heat) to cure high-performance polymers at or near room temperature. Previous processes to form high-performance polyimides and polyesters involved condensation reactions, which are problematic because they involve materials that are toxic, mutagenic, and carcinogenic. Safe handling and disposal of these materials requires the implementation of costly engineering controls. This patented process provides a method of preparing radiation-curable polyesters at ambient temperatures, which does not pose the health risks associated with conventional methods. In addition to being safer to produce, these polyesters have mechanical strength, dimensional stability, low thermal expansion, electrical insulation properties, and high temperature resistance—characteristics that reduce the weight and improve the performance of industrial materials, electronic devices, and machinery.

Researchers at NASA’s Glenn Research Center have patented a method that enables the curing of high-performance polymers at or near room temperature by using ultraviolet light rather than heat to provide the cure energy. Previous processes required high heat and involved toxic materials that led to high processing costs and health risks. This patented process provides a method of preparing radiation-curable polyimides at ambient temperatures, which does not pose health risks associated with conventional methods. These novel polyimides are characterized as having high glass transition temperatures, good mechanical properties, and improved processing in the manufacture of adhesives, electronic materials, and films.

Researchers at NASA’s Glenn Research Center have patented a multilayer system for components exposed to severe environmental and thermal conditions, such as those present in gas turbine engines. A major limitation in the efficiency of current gas turbines is the temperature durability of metallic structural components, such as blades and nozzles, in the engine. While the traditional ceramic thermal barrier coatings that insulate these metallic components allow high-temperature performance, metallic components often experience coating loss resulting from spallation (i.e., cracking) or erosion from oxidation. This patented multilayer system provides environmental protection for substrates comprised of silicon-containing ceramic or metal compounds, providing excellent oxidation resistance and increased durability in high-temperature environments.

Researchers at NASA’s Glenn Research Center have patented a high-solid content, stable polyimide precursor solution that has an unlimited shelf life at room temperature. This solution is particularly useful for the preparation of fibrous composites used in military and civil applications, like aircraft engine components. Previous techniques have produced solutions with a limited shelf life and a tendency toward premature aging at temperatures slightly above room temperature. These techniques are also difficult to adapt to low-cost manufacturing processes such as resin transfer molding. Glenn’s patented polyimide precursor solution solidifies at room temperature and immobilizes reactant monomers, which prevents aging of the solution. This solution can be stored indefinitely at room temperature and quickly warmed up without aging the solution, which is suitable for resin infusion for resin transfer molding. Because of its infinite shelf life, this solid solution can be manufactured in larger quantities for reduced production costs.

Researchers at NASA’s Glenn Research Center have patented mechanically resilient polymeric films that are composed of short, rigid rod segments that alternate with flexible coil segments. These polymers provide superior ion conductivity because the rod and coil segments are highly incompatible, and thus, phase separate to create nanoscale channels for ion conduction. The rod segments provide thermal, dimensional, and mechanical stability, and the coil segments are hydrophilic, which allow the polymers to retain water. By eliminating the need for excess moisture, fuel cell membranes can operate at elevated temperatures, making the fuel cells more efficient. These polymer segments are superior because they reduce the operating temperature of lithium polymer batteries and eliminate the need for flammable solvents in typical battery applications, making fabrication safer, convenient, and more cost effective.

Innovators at NASA’s Glenn Research Center have patented a nickel-based superalloy with a unique combination of versatile heat treatment processing capabilities and superior mechanical properties at elevated temperatures up to 815°C. Particularly useful for advanced disks and rotors in gas turbine engines, the superalloy can provide low solvus temperature for high processing versatility by virtue of its Co and Cr levels. The W, Mo, Ta, and Nb refractory element levels of the superalloy can provide sustained strength, creep, and dwell crack growth resistance at high temperatures—providing a marked improvement over previous methods to modify alloy chemistry for improved strength and time-dependent properties at high temperatures. These prior methods resulted in alloys that are difficult to heat treat, require high-solution temperatures often above 1160°C for coarse grain size, and/or are difficult to quench without forming cracks. This innovation can produce either uniform coarse-grain microstructures maximizing strength and time-dependent properties at high temperatures up to 815°C, or uniform fine-grain microstructures possessing very high strength properties at lower temperatures from 25 to 650°C.

Researchers at NASA’s Glenn Research Center have patented a new system to overlay a coating of nickel aluminide (NiAl) for advanced copper alloys, which provides a high-temperature, environmentally resistant barrier. When used for components in combustion chambers of rocket engines, advanced copper alloys are exposed to high heat flux and gas pressure. Unprotected copper alloy can be degraded by repeated oxidation and reduction cycles (blanching) and by thermal fatigue of channels carrying cryogens. This new system involves cleansing the copper alloy surface, depositing a bond coat on the cleansed surface, depositing a NiAl top layer on the bond coat, and consolidating the top coat and bond coat to form a high-temperature, environmentally resistant thermal barrier coating. Both bond and NiAl layers can be deposited using a low-pressure or vacuum plasma spray.

Researchers at NASA’s Glenn Research Center have patented a method that improves the thermal-oxidative stability of polyimides produced via the Polymerization of Monomer Reactant (PMR) process. This stability is achieved by controlling polymer constituents and providing novel polymer endcaps. High-temperature polyimide matrix composites are used in some structural aircraft parts because of their high specific strength and low density. Presently, conventional polymer endcaps limit the application of polyimides to lower temperature parts of the engine, and limit the polymer life cycle. Glenn’s patented method makes polyimides through polymerization of polyamines, tetracarboxylic dianhydrides, and novel dicarboxylic endcaps. This process controls the degradation of the endcap, resulting in better polyimide resiliency, reduced weight loss, and longer life cycles. The produced polyimides are particularly useful in the preparation of fiber-reinforced, high-temperature composites for use in various engine parts including inlets, fan ducts, exit flaps, and other parts of high-speed aircraft.

Researchers at NASA’s Glenn Research Center have patented a solvent-free process for preparing novel imide oligomers that have a low-melt viscosity and are thus amenable to low-cost processing such as resin transfer molding. Curing the oligomers produces thermoset polyimide resins with high-temperature performance capabilities that are suitable for use in high-quality polymer composites with carbon, glass, or quartz fiber. The unique melt process without a solvent provides a manufacturing advantage over the expensive high boiling solvents previously needed to produce the oligomers. This process also eliminates the need for tedious and high-cost solvent removal.

Researchers at NASA’s Glenn Research Center have patented an alternative and more efficient process for preparing asymmetrical biphenyl tetracarboxylic acids and the corresponding asymmetrical dianhydrides (a-BPDA, a-BTDA, and a-MDPA). The capability of producing these can improve preparation of low-melt viscosity and colorless polyimides for aerospace and electronic applications. By employing a cross-coupling reaction with 3- and 4-substituted o-xylenes in the presence of a catalyst, this patented process exclusively produces asymmetric precursors that are then oxidized or hydrolyzed to produce the corresponding asymmetric tetracarboxylic acids. These acids are subsequently converted to the corresponding dianhydride, a-BPDA, a-BTDA, or a-MDPA in relatively high quantities. Prior processes for creating a-BPDA and other dianhydrides yielded a mixture of asymmetrical and symmetrical dianhydrides, which then required additional, costly processing to separate the isomers. Because this process efficiently produces asymmetrical dianhydrides, such as a-BPDA, the production of polyimides having lower melt viscosities and high glass transition temperatures can be achieved in larger quantities. These superior low-temperature polyimides facilitate resin transfer molding, which is a cost-effective approach in manufacturing components with the desired properties for aerospace and electronic applications.

Researchers at NASA’s Glenn Research Center have patented a process related to the composition and preparation of asymmetric tetracarboxylic acids, the corresponding dianhydrides, and the intermediates of dianhydrides. The dianhydrides of this new process are useful in preparing polyimides used for resin transfer molding in aerospace and electronic applications. Currently, asymmetrical a-BPDA is prepared via an oxidative coupling reaction that yields small amounts of a-BPDA. Consequently, a-BPDA is produced in limited quantities and is not commercially available in sufficient amounts. By using a cross-coupling reaction with 3,4-dimethyl or 2,3-dimethylphenylboronic acid and substituted o-xylenes in the presence of catalysts, this new invention produces a series of asymmetric dianhydrides, not only a-BPDA, but also a-BTDA, a-MDPA and a-6FDA. The capability to produce all of these can improve preparation of low-melt viscosities and colorless polyimides for resin transfer molding (the preferred method for making aerospace components).

Researchers at NASA’s Glenn Research Center have patented a composite fan casing for a turbine engine with a core comprised of many layers of reinforcing fibers bonded with a thermosetting polymeric resin. This fan casing is superior because the fibers are braided in a circumferential direction and include a concentrated stiffening ring, which further reinforces the casing, making it resistant to cracking. Because it effectively employs composite fibers and resin, this casing is lightweight while offering the strength and stiffness required to prevent engine stress and foreign object damage that can cause damage to equipment and injury to personnel. When compared to conventional metal casings, the decrease in the weight of this new casing without decreasing its strength is advantageous for aircraft.

Researchers at NASA’s Glenn Research Center have patented a nickel-based superalloy with increased creep resistance, microstructural stability, oxidation resistance, and improved strength with low density. Properties of the new superalloy exceed those of other nickel-based superalloys currently in production. The improved superalloy embodies all the required characteristics for constructing components of aircraft gas turbine engines and blades that are repeatedly exposed to severe temperatures and environmental conditions. Furthermore, by having low density, the new material does not increase the weight of the engine or aircraft.

Researchers at NASA’s Glenn Research Center have patented a method of fabricating a high-performance carbon and metal and/or metal oxide nanoparticle composite material for the production of anodes for lithium-ion batteries. Anodes made from this improved composite can carry high current densities, have high cycle life, and have high reversible and low irreversible capacities. These properties are achieved by using a carbon material as a constituent part of the composite, chemically treating the carbon material to receive nanoparticles, incorporating nanoparticles into the chemically treated carbon material, and removing surface nanoparticles from an outside surface of the carbon material. Compared to lithium-ion batteries that use carbon as an anode, this new composite will enable longer times between recharging and produce batteries that are smaller with higher capacities.