Composite Insulated Conductor

These extreme fire-resistant insulation systems show promise for use in high-voltage, high-power systems.

NASA's Langley Research Center has developed a new class of polyimide composite electrical insulation materials for wires, cable, and bus pipe. These new insulation materials have been shown to withstand a 12-hour gas flame test while maintaining structural and electrical circuit integrities. These extreme fire-resistant insulation systems show promise for use in high-voltage, high-power systems. They can improve survivability and continuity of the electrical power supply. Besides fire resistance, these materials also provide weight and space savings because of their lightweight nature and exceptionally high-performance capability. NASA developed the wire insulation for exploration and space operations; however, the technology also has applicability to other high-voltage, high-power systems for maritime, high-rise building construction, and other industries.

Posted in: Briefs, Materials, Electric cables, Wiring, Electric cables, Wiring, Composite materials, Insulation, Durability, Durability

Multifunctional Platelet Composites for Tin Whisker Mitigation

Applications include consumer electronics, automotive, and electronic weapons systems.

To comply with the Restriction of Hazardous Substances (RoHS) directive, pure tin is replacing lead-tin alloys in commercial electronic devices. Unfortunately, tin can grow whiskers that can lead to electrical short circuits or metal vapor arcing, both of which threaten the long-term reliability of electronic systems, and cause critical systems to fail catastrophically. A current method of whisker mitigation utilizes coatings based on glassy or rubbery unfilled polymers; such coatings are not impenetrable to tin whiskers.

Posted in: Briefs, Materials, Electronic equipment, Electronic equipment, Coatings Colorants and Finishes, Coatings, colorants, and finishes, Composite materials, Tin alloys

Electrically Conductive, Optically Transparent Polymer/Carbon Nanotube Composites

A templated growth process provides uniform-sized carbon nanotubes.

NASA's Langley Research Center researchers have developed a novel method for making carbon nanotubes that are very uniform in size. A template is used to guide the carbon nanotube growth so that all nanotubes are uniform in size. The carbon nanotubes can be used as-grown, uniformly dispersed, and aligned within the template or isolated from the template for use as carbon nanotubes. The solution-based process uses sugar as a carbon source, does not require vacuum, and is thus simple and low-cost in nature.

Posted in: Briefs, Materials, Fabrication, Composite materials, Conductivity, Nanomaterials

Space Vehicle Heat Shield Having Edgewise Strips of Ablative Material

Edgewise strips of PICA ablator eliminate gaps in the capsule heat shield.

An alternate heat shield concept for the Orion space vehicle is to use interlocking blocks of Phenolic Impregnated Carbon Ablator (PICA). The blocks are independent from one another and there is a defined gap inches between the blocks. That gap poses serious problems to the vehicle and crew if gases flow between the PICA blocks. This invention is a simple yet robust invention for PICA block gap filler. Strips of preconditioned PICA blocks are positioned edgewise to fill gaps between PICA blocks to provide a gap filler substance that allows thermal expansion, and satisfies mechanical strain between the PICA tiles and substructure.

Posted in: Briefs, Materials, Thermal management, Thermal management, Product development, Insulation, Spacecraft

Mechanically Strong, Thermally Stable, and Electrically Conductive Nanocomposite Structure and Method of Fabricating Same

This technology can be used in automobiles, launch vehicles, advanced aerospace vehicles, aircraft, and spacecraft.

NASA's Langley Research Center has developed a method for producing multifunctional, structural, thermally stable nanocomposites with aligned carbon nanotubes. The invention improves upon current state-of-the-art graphite fiber composites by providing the same lightweight and mechanically strong characteristics, but also adds thermal stability and electrical conductivity. Thus, the invention can be used to provide a new class of mechanically strong, thermally stable, and electrically conductive nanocomposites.

Posted in: Briefs, Materials, Fabrication, Composite materials, Graphite, Materials properties, Nanomaterials

Improved Cast Stainless Steel Alloys

Applications include chemical/petrochemical production systems, gas turbine engines, and high-performance alloys.

At high temperatures, currently available cast stainless steel alloys used for engine component applications do not have the long-term stability of their original castings, and are lacking in their ability to resist deformation and cracking from extreme temperature changes. There is a need for high-strength, oxidation-resistant, and crack-resistant cast alloys for use in internal combustion engine components such as exhaust manifolds and turbocharger housings, gas-turbine engine components such as combustor housings, and other components that must function in extreme environments for prolonged periods of time.

Posted in: Briefs, Materials, Casting, Advanced high-strength steels, Alloys, High-strength low-alloy steel, Engine components, Durability, Durability

Highly Porous and Mechanically Strong Ceramic Oxide Aerogels

These materials provide improved environmental durability and elasticity for aerospace and terrestrial applications.

NASA's Glenn Research Center (GRC) has developed and produced ultra-lightweight polymer cross-linked aerogels (X-Aerogels). These mechanically robust, highly porous, low-density materials are three times denser than native aerogels, but more than 100 times stronger. Aerogels are ultra-lightweight glass foams with extremely small pores (on the order of 10 to 50 nanometers). These materials are extremely good thermal insulators, with R values ranging from 2 to 10 times higher than polymer foams. Unlike multilayer insulation, aerogels do not require a high vacuum to maintain their low thermal conductivity, and can function as good thermal insulators at ambient pressure. In addition, they are good electrical insulators and have low refractive indices, both approaching values close to air. Aerogels are also excellent vibration-damping materials. Traditional aerogels, however, suffer fragility and poor environmental durability.

Posted in: Briefs, Materials, Ceramics, Conductivity, Foams, Lightweight materials, Materials properties, Polymers

Asymmetric Dielectric Elastomer Composite Material

This material has applications in artificial muscle and hearts, physical therapy/rehab devices, morphing aircraft, robotics, and sensors.

This electronic active material converts a voltage input to a mechanical force and mechanical displacement output. As compared to prior dielectric elastomer (DE) systems, the material has reduced electrode spacing, which lowers significantly the required operating voltage. In addition, the inclusion of a combination of conducting and/or non-conducting reinforcing fibers greatly enhances the strength of the material, without weight penalty.

Posted in: Briefs, Materials, Voltage regulators, Voltage regulators, Composite materials, Elastomers, Fibers

Method of Creating Micro-Scale Silver Telluride Grains Covered with Bismuth Nanoparticles

Potential applications include power generation and waste heat recovery, and refrigeration and cooling.

NASA Langley Research Center has developed a novel thermoelectric (TE) material utilizing micro-scale silver telluride grains covered with bismuth nanoparticles. These materials have unique advantages in directly converting any level of thermal energy into electrical power and solid-state cooling by a reverse mode. Although thermoelectric devices are regarded advantageously with their high reliability, their lack of moving parts, and their ability to scale to any sizes, the devices’ energy conversion efficiency remains generally poor.

Posted in: Briefs, Materials, Electric power, Thermodynamics, Thermodynamics, Materials properties, Nanomaterials

Polyimides Derived from Novel Asymmetric Benzophenone Dianhydrides

NASA's Glenn Research Center invites companies to license or establish partnerships to develop its patented high-temperature, low-melt imide resins for fabrication of automotive components. Produced by a solvent-free melt process, these resins exhibit high glass transition temperatures (Tg = 370 to 400 °C), low melt viscosities (10 to 30 poise), long pot-life (1 to 2 hours), and can be easily processed by low-cost RTM and vacuum-assisted resin transfer molding (VARTM). These RTM resins melt at 260 to 280 °C, and can be cured at 340 to 370 °C in 2 hours without releasing any harmful volatile compounds.

Posted in: Briefs, Materials, Heat resistant materials, Materials properties, Resins

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