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materials and coatings
bug splatter
Novel Copolyimide Surface Modifying Coating
Accumulation of undesirable species such as insect residue is mitigated by use of copolyimide coatings incorporating fluorine and silicon surface modifying agents (SMAs) in a novel chemical formulation. The coating minimizes adhesion while at the same time maintaining the bulk properties of the polyimide coating. The specific SMAs used here are designed to be thermodynamically drawn to the coating surface. Further, the SMAs react chemically with the polymer backbone and are thus chemically bonded, so the SMAs will not evaporate or migrate out of the coating material. The coating adheres well to a range of relevant materials, including aluminum, composites and plastics.
manufacturing
Friction Stir Welding Apparatus
Abnormal Grain Growth Suppression in Aluminum Alloys
Heat treatment of the deformed welds is desirable in order to restore the properties of the alloy negatively affected in the weld region. In these alloys, abnormal grain growth frequently occurs in friction stir welds during solution heat treatment, and is known to degrade key materials properties, such as strength, ductility and toughness. The innovation of inserting an intermediate annealing step covered here reduces abnormal grain growth during post-welding heat treatment, thereby allowing optimum mechanical properties. This is important where Al-Li alloys (and other heat treatable alloys) are friction stir welded followed by deformation processing and high performance, high reliability structural components are required for aerospace vehicles.
manufacturing
Fabrication of Fiber-Metal Laminates with Non-Autoclave Processes
Fabrication of Fiber-Metal Laminates with Non-Autoclave Processes
The FMLs resulting from the NASA process have similar properties to traditionally produced metal/composite hybrid laminates including, as compared to either the composite or metal only structures, improved load carrying capability, lighter weight, improved stiffness, improved impact resistance and damage tolerance, and improved permeation resistance. The NASA process can be applied to various FML types, including GLARE (glass, aluminum, epoxy), and TIGR (titanium, graphite). Typical manufacturing processes are costly and complex shapes are hard to produce, whereby the NASA process enables use of these kinds of laminates without an autoclave or press, thus increasing the size that can be produced and decreasing the cost. The resin pathways in the foils enable connection between the plies that can improve the interlaminar strength of the final part. Functionally the NASA process creates resin columns in the transverse direction of the plies. NASA is working to optimize the final properties by varying the size and distribution of the pathways.
materials and coatings
Laptop flash drive
Decorated Carbon Nanotubes
NASA's technology is a process for depositing nanometer-sized metal particles onto a substrate in the absence of aqueous solvents, organic solvents, and reducing agents, and without any required pretreatment of the substrate. It involves first mixing carbon and an organometallic compound (silver, gold, platinum, palladium, cobolt, nickel) at specific concentrations followed by a thermal treatment. The resulting materials are novel structures that consist of the carbon allotrope with zero valence metallic particles distributed on the surface of the carbon allotrope. In the case of the antenna application, the conducting elements are placed directly into the substrate. Other applications such as catalysts for chemical reactions and polymerizations are possible.
materials and coatings
Front Image ARC-16132-1
Surface Densification Of Phenolic Impregnated Carbon Ablator (PICA)
The graded Thermal Protection System (TPS) offers a lower density than comparable state-of-the-art TPS systems operating at similar maximum heating conditions. This approach is straight forward in terms of processing and surface-treatment application and can be applied to machine PICA materials without having an effect on the final tolerance. The process results in increased usability and handling since standard uncoated PICA is relatively weak. Surface-densified PICA provides an approach for improvements in the robustness for the baseline CEV heat shield. A graded approach eliminates the need for joints and/or bonding agents between material plies. PICA surface densification offers robust mechanical protection against transit damage, handling damage, and in-flight object damage.
power generation and storage
solar cell
Advanced Efficiency Flexible Solar Film
By varying the number, type, orientation and functionality of various solar panel materials, a diverse family of devices can be constructed that can be tailored for many operational concepts. Various solar panel designs can be constructed that include active, cooling, and solar absorbance layers with tailored characteristics. This flexibility is achieved by arranging multiple solar absorbance layers that are coupled to polymer composite solar absorbance layers. The polymer composite can contain metal salts, oxides and/or carbon nanotubes as needed for various applications. The polymer can be chosen for flexibility or stiffness characteristics as needed by the designer. Configurations can include cooling layers with zinc oxides, indium oxides, and/or carbon nanotubes coupled between active layers. The carbon nanotubes can be aligned in a particular direction of the second cooling layer to achieve a heat flow bias. The cooling layer may be grooved to match other functional layers to increase the surface area for heat transfer.
materials and coatings
Thermal Protection Systems
High Efficiency Tantalum-based Ceramic Composite (HETC) Structures
The various embodiments of this technology include insulating composites capable of surviving high heating rates and large thermal gradients in the aeroconvective heating environment that entry vehicles are exposed to characteristically. The tantalum-based ceramics contain tantalum disilicide, borosilicate glass and, optionally, molybdenum disilicide. The components are milled, along with a processing aid to facilitate sintering, then applied to a surface of a porous substrate, such as a fibrous or open-pored silica, carbon, aluminosilicate, silicon carbide or silicon oxycarbide substrate, as well as other substrates of silicon/carbon compositions. Following application, the coating is then sintered on the substrate. The composite structure is substantially impervious to hot gas penetration and capable of surviving high heat fluxes.
materials and coatings
Bug on metal
Chemical and Topographical Surface Modifications for Insect Adhesion Mitigation
The technology is a method of mitigating insect residue adhesion to various surfaces upon insect impact. The process involves topographical modification of the surface using laser ablation patterning followed by chemical modification or particulate inclusion in a polymeric matrix. Laser ablation patterning is performed by a commercially available laser system and the chemical spray deposition is composed of nanometer sized silica particles with a hydrophobic solution (e.g. heptadecafluoro-1,1,2,2-tetrahydrodecyltriethoxysilane) in an aqueous ethanol solution. Both topographic and chemical modification of the substrate is necessary to achieve the desired performance.
materials and coatings
Bugs on windshield
Hydrophobic Epoxy Coating for Insect Adhesion Mitigation
This technology is a copolymeric epoxy coating that is loaded with a fluorinated aliphatic chemical species and nano- to microscale particle fillers. The coating was developed as a hydrophobic and non-wetting coating for aerodynamic surfaces to prevent accumulation of insect strike remains that can lead to natural laminar flow disruption and aerodynamic inefficiencies. The coating achieves hydrophobicity in two ways. First, the fluorinated aliphatic chemical species are hydrophobic surface modification additives that preferentially migrate to the polymer surface that is exposed to air. Secondly, the incorporation of particle fillers produces a micro-textured surface that displays excellent resistance to wetting. Combined, these two factors increase hydrophobicity and can also be used to readily generate superhydrophobic surfaces.
materials and coatings
Cryogenic Pipe
Polyamide Aerogels
Polyamides are polymers that are similar to polyimides (another polymer that has been developed for use in aerogels). However, because the amide link is a single chain while the imide link is a ring structure, polyamide aerogels can be made less stiff than polyimides, even though a similar fabrication process is used. The precursor materials can be made from any combination of diamine and diacid chloride. Furthermore, NASA Glenn researchers have found methods for using combinations of diamines and disecondary amines to produce polyamide aerogels with tunable glass transition temperatures, for greater control of features such as flexibility or water-resistance. In the first step of the fabrication process, an oligomeric solution is produced that is stable and can be prepared and stored indefinitely as stock solutions prior to cross-linking. This unique feature allows for the preparation and transport of tailor-made polyamide solutions, which can later be turned into gels via the addition of a small amount of cross-linker. When the cross-linking agent is added, the solution can be cast in a variety of forms such as thin films and monoliths. To remove the solvent, one or more solvent exchanges can be performed, and then the gel is subjected to supercritical drying to form a polyamide aerogel. NASA Glenn's polyamide aerogels can be fully integrated with the fabrication techniques and products of polyimide aerogel fabrication, so hybrid materials which have the properties of both classes are easily prepared. As the first aerogels to be composed of cross-linked polyamides, these materials combine flexibility and transparency in a way that sets them apart from all other polymeric aerogels.
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