Materials & Coatings

A report discusses the development of the GENOA-PFA computer program, which was described in "Software for Simulating Progressive Fracture in Braided PMCs" (LEW-16845), NASA Tech Briefs, Vol. 24, No. 3 (March 2000), page 52; and "Update on a Progressive-Failure-Analysis Software System...

Carbon-fiber-filled polymers made from ethylene propylene diene monomer (EPDM) have been found to be useful as ablative thermal-insulation materials. Like the silica-filled EPDM polymers described in the preceding article, these polymers have been investigated as candidates to replace some...

A flexible design concept and an associated method of fabrication have been conceived as means to satisfy growing demands for lightweight composite-material pipes for corrosive and cryogenic liquids. The design concept and method can be applied to produce piping systems capable of...

An advanced technique of deep reactive-ion etching (DRIE) has been developed for fabricating smooth vertical walls in silicon wafers. These walls are suitable for use as bounding surfaces of optical waveguides in photonic and optoelectronic devices. The roughness of a typical 8-µm-high...

An improved method of plasma chemical-vapor deposition (CVD) of a thin film of boron carbide has been devised. Boron carbide is useful because it is hard, is electrically insulating, withstands high temperature, and resists chemical attack. Plasma CVD of boron carbide involves the thermal...

A report discusses a proposed nesting-hoop solar sail that would be used to propel a spacecraft on a deep-space mission. The nesting-hoop design concept was chosen as one that would afford a desired combination of small mass and compact stowage during launch. The sail would include multiple disks, each comprising a thin...

Scientists have developed a derivative of the lithium-ion cell that could prove useful in spaceflight and commercial applications in which it is planned to use oxygen batteries based on solid polymer electrolytes. This derivative cell, which contains a solid polymer electrolyte and an oxygen gas...

NASA scientists, who are very concerned with the increasing hazard of impacts of orbital debris impact on spacecraft, have designed the "stuffed Whipple" shield — a lightweight, relatively inexpensive alternative to simple aluminum meteoroid/orbital-debris (M/OD) shield. The stuffed Whipple...

Lightweight, inflatable tubular structural components containing tape-spring reinforcements are undergoing development. The basic (without tape-spring reinforcement) tubular components are made, variously, of aluminum laminates or composite materials and are under consideration for use in...

A report presents additional information on the GENOA-PFA computer program, which was described in "Software for Simulating Progressive Fracture in Braided PMCs" (LEW-16845), NASA Tech Briefs, Vol. 24, No. 3 (March 2000), page 52. On the basis of material-property data, finite-element...

Carbon nanotubes (also known as "bucky tubes") have shown promise for use as anode materials in rechargeable lithium-ion power cells. In comparison with graphite and other forms of carbon used under identical conditions, bucky tubes exhibit greater specific discharge capacity and greater...

Aerogels with gradients in density have been produced in experiments, as part of an effort to develop materials that will be used in outer space to capture particles traveling at high speeds for the STARDUST mission.

An improved method of manufacturing high-temperature superconductors of general composition YBa2Cu3O7— x and various grain structures has been devised. This method involves mixing, pressing, and heating of Y2O3, CuO, and Ba(NO3)2 powders. This method is easier than an older method that...

An improved process for waterproofing ceramic materials — especially lightweight ceramic insulation materials in both rigid (tile) and flexible (blanket) form — has been invented. In this process, traditional waterproofing agents are used, but before the waterproofing agents are applied, the...

Two reports present additional details about the method described in "Reaction-Forming Method for Joining SiC-Based Ceramic Parts" (LEW-16661), NASA Tech Briefs, Vol. 23, No. 3 (March 1999), page 50. To recapitulate: A carbonaceous mixture (typically a paste) is applied to a joint between parts....

LIPS (LIFE PREDICTION SOFTWARE) is a computer program for predicting the life of an object that is made of a unidirectional-fiber/metal-matrix composite (MMC) material and that is subjected to mechanical loading along the fiber direction. The program is derived from a theory formulated to be...