Materials

A more versatile delivery system for fused deposition has recently been developed. This system uses a very stiff, precise, and compact actuator to drive a small piston/cylinder extruder that has a heated nozzle. Because feed rods are used as the feed material, this...

A report proposes the use of muscle wires as mechanical actuators for planetary-exploration robots. Muscle wires are commercially available in kit form in the hobby market, and have been described (though not explicitly called "muscle wires") in previous articles in NASA Tech Briefs. A muscle wire is...

A low-density, creep-resistant ceramic composite material has been developed as a prototype of such materials for use at high temperatures in the next generation of aircraft engines. The material consists of Nextel (or equivalent) ceramic fibers in a matrix that is, itself, a composite of...

A report describes experiments on the wear-reducing performances of six additives to perfluoropolyether (PFPE)-based fluids in the boundary-lubrication regime. The additives were a phosphate, a thiophosphate, a β-diketone, a benzothiazole, an amide/thiol, and a sulfite. Each additive was...

Two methods have been developed to purify large batches of technical-grade carbon tetrachloride. The relatively impure carbon tetrachloride that had been purchased for use in infrared analysis of dissolved hydrocarbons proved that it could be purified. One method is spinning-band distillation, which is...

A nitrogen-beam source has been developed to significantly improve the synthesis of wide-band-gap nitrides.

An accelerated-testing method has been developed for evaluating the effectiveness of various measures taken to prevent the corrosion of steel reinforcing bars ("rebars") cast into concrete. Such measures can include chemical admixtures incorporated into the concrete, coatings, penetrants,...

A report describes research on selected compounds as additives to perfluoroalkyether (PFPAE) fluids that are used as synthetic lubricants for metal parts. Additives are needed to inhibit both thermo-oxidative degradation of, and corrosion of metals by, the PFPAE fluids in the presence of...

Designing metal-matrix composites into actual components requires both experimental and analytical characterization of the behavior of these composites. This report describes mathematical modeling and experimental characterization of the elastoplastic behaviors of composite materials made...

The Integrated Particulate Composite Analyzer (ICAN/PART) computer program is a modified version of the Integrated Composite Analyzer (ICAN) program (LEW-15592/LEW-15832), which was developed to conduct analyses of the micromechanics of fiber-reinforced polymer-matrix composite materials....