Materials & Manufacturing

The term "Molecular-Sieve Type 3Å" denotes a clay-based, zeolite material that revolutionizes a fluid-purification process by removing trace water and iron from nitrogen tetroxide/nitric oxide (MON-3) mixtures used as oxidizer components of spacecraft propellants. Older processes of this type removed only water or iron...

Scientists have developed a type of composite graphite anode that will benefit the U.S. space program and private industry by increasing the rechargeability of lithium-ion batteries. Rechargeable lithium-ion batteries, which are used on the space shuttle and Space Station, are also used in...

Experiments have shown that electrically conductive polymers with water-soluble fractions can be synthesized by polymerization of pyrrole or aniline in the presence of lignosulfonic acid, which is a polymeric acid that can be derived relatively easily from the spent sulfite liquor byproducts...

Several improvements have been proposed for the fabrication process known as "rapid prototyping." In this process, a model or prototype of a solid object is built up by controlled ejection of molten polymeric material through programmed orifices to form patterned layers. The second layer is deposited on top of the...

Reports labeled as chapters 2, 3, 4, 7, 8, 9, and 10 of a NASA technical memorandum that addresses topics in tribology have been compiled into a document that emphasizes those aspects of the subject matter that pertain to chemical-vapor-deposited (CVD) diamond and diamond-like films. The...

White Sands Test Facility (WSTF) scientists have developed an energy-absorbing laminated shell that is a prototype of lightweight, inexpensive, and removable covers to shield and otherwise protect carbon-composite overwrapped pressure vessels (COPVs). Although COPVs are superior to metal...

Nonevaporable getters have been proposed for use in maintaining vacuum inside hermetically sealed microelectromechanical systems (MEMS) that rely on vacuum for proper operation. A vibratory microgyroscope is an example of such a MEMS. The proposed getters could also be used in such vacuum...

A report presents results of research on carbonate-based electrolytes to improve the low-temperature-performances of lithium-ion rechargeable electrochemical cells. The loss of performance with decreasing temperature is attributable largely to a decrease of ionic conductivity and the increase...

The Materials Science Division (MSD) at Kennedy Space Center is developing a computer system to maintain a material-science data base coupled with a user-friendly interface on the World Wide Web. The system is designed to eliminate the need for time-consuming and expensive distribution of,...

In a proposed method of tailoring some of the mechanical properties of metal-matrix, oxide-matrix, and ceramic-matrix composite materials, Kirkendall defects (microscopic pores as described below) would be introduced into thin interfacial layers between the fibers and the matrices. This...

Coating alumina fibers with sputtered metal has been proposed as a means to enable the fibers to retain more strength when the fibers are incorporated into metal-matrix composites. If the alumina fibers could be made to retain more strength, then it would be possible to manufacture such...

A report presents updated information on the developments described in "MoSi2-Based Composite Materials for Aircraft Engines" (LEW-16617),NASA Tech Briefs, Vol. 22, No. 9 (September 1998), page 62. To recapitulate: Hybrid composites of (1) SiC-based fibers within (2) matrices that...

Probabilistic Ceramic Matrix Composite Analyzer (PCEMCAN) is a user-friendly computer program that predicts uncertainties in the mechanical and thermal properties of ceramic-matrix composite (CMC) materials. These materials are candidates for fabrication of structural components that will be...