Materials & Coatings

White, Electrically Conductive, Radiation-Stable, Thermal Control Coating

Goddard Space Flight Center, Greenbelt, Maryland A highly reflective, white conductive coating system was developed using a layered approach with a combination of commercially available white conductive pigments within a conductive binder system. The top coating is a space-stable, radiation-resistant, highly reflective coating that has been tailored to provide optimum reflectance properties and meet vacuum thermal surface resistivities. The combined layer is a mixture of a highly reflective, electrically dissipative coating and a moderately reflective but highly conductive pigment in a conductive binder. A second, underlying layer of conductive white coating offers optimum adhesion to metal substrates and the topcoat. The system vacuum resistivity at room temperature is approximately 1 × 109 ohms/sq, and has a solar absorptance of less than 0.13 as measured on a Cary 5000 spectrophotometer.

Posted in: Briefs, TSP, Thermoelectrics, Coatings & Adhesives, Materials, Thermal management, Coatings, colorants, and finishes, Conductivity


Plasma-Assisted Thin Film Coatings to Create Highly Hydrophobic Porous Structures

Multiple samples can be coated in this manner. John H. Glenn Research Center, Cleveland, Ohio Gas-distribution layers (GDLs) are water-management structures used in fuel cells and electrolyzers. GDLs are critical components that prevent flooding of the fuel cell electrode by product water, thus preserving open channels for reactant gas to reach the electrode. Typically, GDLs are electrically conductive papers (metal or carbon) having a fine pore structure. Extremely fine pores in some GDL materials are difficult to fully infiltrate with Teflon (PTFE). These materials are typically wet-proofed by coating with hydrophobic materials (e.g. PTFE). This is usually accomplished by immersing the raw paper in a PTFE emulsion. Completeness of wet-proofing by immersion in emulsion can be limited, because fine pores will filter out the PTFE particles.

Posted in: Briefs, TSP, Coatings & Adhesives, Materials, Fuel cells, Coatings, colorants, and finishes


High-Performance Photocatalytic Oxidation Reactor System

Airborne volatile organic chemicals are oxidized using blue LEDs, fiber optics, and visible light-activated catalysts for space and terrestrial air purification. Marshall Space Flight Center, Alabama As crewed space missions extend beyond low Earth orbit, the need to reliably recover potable water is critical. Aboard the International Space Station (ISS), the water is recycled from cabin humidity condensate, urine distillate, and hygiene wash wastes. In spacecraft cabin air environments, off-gassing from equipment, human metabolism, and human personal care products contributes to significant airborne concentrations of volatile organic compounds (VOCs). These polar and water-soluble compounds ultimately dissolve into the humidity condensate and stress the process load, logistics costs, and lifecycle requirements of the water processing systems. The aim of this effort was to develop the High Performance Photocatalytic Oxidation Reactor System (HPPORS) technology for the destruction of airborne VOCs prior to reaching the water processing systems. This innovation will reduce the logistics costs and lifecycle requirements of water processing systems, and help extend NASA missions to include long-duration space habitation and lunar and Mars colonization missions.

Posted in: Briefs, Aerospace, Green Design & Manufacturing, Recycling Technologies, Remediation Technologies, LEDs, Lighting, Materials, Fiber Optics, Photonics, Light emitting diodes (LEDs), Catalysts, Volatile organic compounds


Reducing Interconnection Weight in Autosports

In Formula 1 and other autosports, weight reduction is critical to competitive advantage. A few grams saved here and a few more saved there can add up to significant savings. There is also a move toward high-density packaging of electronics parts. As the electronics content of cars increases, the natural drive is to miniaturize the package to gain maximum efficiency in the use of space.

Posted in: Articles, Electronic Components, Electronics, Composites, Fiber Optics, Connectors and terminals, Electric cables, Composite materials, Lightweighting, Motorsports


Watching Alloys Change Could Lead to Better Metals

If you put a camera in the ice machine and watched water turn into ice, the process would look simple. But the mechanism behind liquids turning to solids is actually quite complex, and understanding it better could improve design and production of metals. A recent investigation aboard the International Space Station (ISS) involved experiments using transparent alloys to observe microstructures that form at the point the material solidifies.

Posted in: UpFront, Materials, Physical Sciences


Optical Fiber for Solar Cells

These materials enable new solar-powered devices that are small, lightweight, and can be used without connection to existing electrical grids. Ames Research Center, Moffett Field, California Polymeric and inorganic semiconductors offer relatively high quantum efficiencies, and are much less expensive and versatile to fabricate than non-amorphous silicon wafers. An optical fiber and cladding can be designed and fabricated to confine light for transport within ultraviolet and near-infrared media, using evanescent waves, and to transmit visible wavelength light for direct lighting.

Posted in: Briefs, Energy, Energy Storage, Solar Power, Materials, Fiber Optics, Physical Sciences, Solar energy, Fibers, Polymers, Semiconductors


Carbon Nanotube Tower-Based Supercapacitor

A new technology to create electrochemical double-layer supercapacitors is provided using carbon nanotubes as electrodes of the storage medium. This invention allows efficient transport between the capacitor electrodes through the porous nature of the nanotubes, and has a low interface resistance between the electrode material and the collector. Carbon nanotubes directly grown on a metal surface are used to improve the supercapacitor performance. The nanotubes offer a high surface area and usable porosity for a given volume and mass, both of which are highly desirable for supercapacitor operation.

Posted in: Briefs, Energy, Energy Storage, Materials, Nanotechnology, Physical Sciences, Ultracapacitors and supercapacitors, Metallurgy, Nanomaterials


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