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


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


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


Product of the Month: March 2015

Instron, Norwood, MA, introduced the AVE 2 strain measurement system that conforms to testing standards such as ISO 527, ASTM D3039, and ASTM D638. The video extensometer utilizes patented measurement technology, and adapts to the normal fluctuations of indoor environmental conditions. It can be adapted to any testing machine that uses a ±10V analog input. Designed to reduce errors from thermal and lighting variations, the device uses the real-time 490-Hz data rate while achieving a 1-micron accuracy. It allows for testing under multiple environmental conditions and can be used for strain measurement with Digital Image Correlation (DIC). The device measures both modulus and strain-to-failure of most materials including plastics, metals, composites, textiles, films, and bio-materials.

Posted in: Products, Manufacturing & Prototyping, Materials, Measuring Instruments


Researcher Spotlight: Atom­Thick Material Offers 2D Imaging Possibilities

Rice University scientists have developed a two-­dimensional, atom­-thick, light-­sensitive material called CIS, a single­-layer matrix of copper, indium, and selenium atoms. Sidong Lei, a graduate student, also built a prototype — a three-­pixel charge­-coupled device (CCD) sensor — to prove the material’s ability to capture an image. The optoelectronic memory material may be the basis for future flat imaging devices and two­-dimensional electronics.

Posted in: Articles, Imaging, Materials, Sensors


Customizing Visual 3D Optical Coatings

There are many ways to coat an optic and optimize the coating for a specific application, some more interesting than others. But any thin film coating process requires raw materials, coating capabilities, deposition chamber(s), coating software, a spectrophotometer, and an efficient production system that can produce the desired coating or effect while keeping within the customer’s requisite specifications. This article will focus on the challenge of customizing a non-polarizing cube beamsplitter for a 3D visual application and detail the steps taken to make this challenge a reality.

Posted in: Articles, Features, Coatings & Adhesives, Materials, Optics, Photonics


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


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