Materials & Coatings

Microsphere Insulation Panels

Thermal performance and lifetime exceed those of foam insulation. Microsphere insulation panels (MIPs) have been developed as lightweight, long lasting replacements for the foam and vacuum-jacketed systems heretofore used for thermally insulating cryogenic vessels and transfer ducts. Whether preformed or applied in place, foam insulation deteriorates fairly rapidly: on cryogenic transfer lines, it has a life expectancy of about three years. Vacuum-jacketed insulation is expensive and heavy. For both foam and vacuum-jacketed insulation, intensive maintenance is necessary to keep performance at or near its original level. Relative to a polyurethane foam insulation panel, a comparable MIP offers greater thermal performance and longer service life at approximately the same initial cost.

Posted in: Briefs, Materials, Insulation, Lightweight materials, Materials properties


Single-Wall Carbon Nanotube Anodes for Lithium Cells

Capacities are greater than those of graphite anodes. In recent experiments, highly purified batches of single-wall carbon nanotubes (SWCNTs) have shown promise as superior alternatives to the graphitic carbon-black anode materials heretofore used in rechargeable thin-film lithium power cells. The basic idea underlying the experiments is that relative to a given mass of graphitic carbon-black anode material, an equal mass of SWCNTs can be expected to have greater lithium-storage and charge/discharge capacities. The reason for this expectation is that whereas the microstructure and nanostructure of a graphitic carbon black is such as to make most of the interior of the material inaccessible for intercalation of lithium, a batch of SWCNTs can be made to have a much more open microstructure and nanostructure, such that most of the interior of the material is accessible for intercalation of lithium. Moreover, the greater accessibility of SWCNT structures can be expected to translate to greater mobilities for ion-exchange processes and, hence, an ability to sustain greater charge and discharge current densities.

Posted in: Briefs, TSP, Materials, Lithium-ion batteries, Nanomaterials, Test procedures


Thermally Stable Piezoelectric and Pyroelectric Polymers

Neither mechanical nor solvent treatment is necessary for orientation of polymer molecules. A class of thermally stable piezoelectric and pyroelectric polymers, and an improved method of making them, have been invented. These polymers can be used as substrates for a wide variety of electro- mechanical transducers, sensors, and actuators.

Posted in: Briefs, Materials


Combustion Synthesis of Ca₃(PO₄)₂ Net-Shape Surgical Implants

More-biocompatible materials are produced in fewer processing steps.ASelf-propagating high-temperature combustion synthesis (SHS) is the basis of a method of making components of porous tricalcium phosphate [Ca3(PO4)2] and related compounds in net sizes and shapes for use as surgical implants that are compatible with bone. Ca3(PO4)2-based materials are among those preferred for use in orthopedic, restorative, and reconstructive surgery. As explained below, the SHS method offers advantages over prior methods of manufacturing Ca3(PO4)2-based surgical implants.

Posted in: Briefs, TSP, Materials, Prostheses and implants, Surgical procedures, Forming, Biomaterials


Designing Cure Cycles for Matrix/Fiber Composite Parts

This methodology enables production of void-free laminates. A methodology has been devised for designing cure cycles to be used in the fabrication of matrix/fiber composite parts (including laminated parts). As used here, “cure cycles” signifies schedules of elevated temperature and pressure as functions of time, chosen to obtain desired rates of chemical conversion of initially chemically reactive matrix materials and to consolidate the matrix and fiber materials into dense solids. Heretofore, cure cycles have been designed following an empirical, trial-and-error approach, which cannot be relied upon to yield optimum results. In contrast, the present methodology makes it possible to design an optimum or nearly optimum cure cycle for a specific application.

Posted in: Briefs, Materials, Fabrication, Heat treatment, Composite materials, Fibers


Cleaning Carbon Nanotubes by Use of Mild Oxygen Plasmas

Mildness of the plasmas is the key to cleaning without destruction.Experiments have shown that it is feasible to use oxygen radicals (specifically, monatomic oxygen) from mild oxygen plasmas to remove organic contaminants and chemical fabrication residues from the surfaces of carbon nanotubes (CNTs) and metal/CNT interfaces. A capability for such cleaning is essential to the manufacture of reproducible CNT-based electronic devices.

Posted in: Briefs, TSP, Materials


Generating Aromatics From CO₂ on Mars or Natural Gas on Earth

The terrestrial version may make it economical to recover some natural-gas deposits.“Methane to aromatics on Mars” (“METAMARS”) is the name of a process originally intended as a means of converting Martian atmospheric carbon dioxide to aromatic hydrocarbons and oxygen, which would be used as propellants for spacecraft to return to Earth. The process has been demonstrated on Earth on a laboratory scale. A truncated version of the process could be used on Earth to convert natural gas to aromatic hydrocarbon liquids. The greater (relative to natural gas) density of aromatic hydrocarbon liquids makes it more economically feasible to ship them to distant markets. Hence, this process makes it feasible to exploit some reserves of natural gas that, heretofore, have been considered as being “stranded” too far from markets to be of economic value.

Posted in: Briefs, Materials


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