Materials & Coatings

Access our comprehensive library of technical briefs on materials and coatings, from engineering experts at NASA and government, university, and commercial laboratories.

Briefs: Materials
Stable Ohmic Contacts on SiC Devices for High Temperatures

Ti3SiC2 has been proposed as a mate- rial for ohmic contacts on SiC-based electronic and microelectromechanical devices intended to operate at temperatures >600 °C and/or in corrosive environments. Although SiC is stable and devices made of SiC are capable of...

Briefs: Materials
Development of Alternatives to Hydrazines as Propellants

A brief report summarizes an investigation of less-toxic alternatives to toxic monopropellant fluids used in launch vehicles, upper stages, and spacecraft propulsion. The toxic fluids in question are (1) hydrazine and its derivatives, used, variously, as fuels or by themselves as...

Briefs: Materials

An apparatus has been developed as a means of controlling the partial pressure of CO2 (pCO2) in air in a closed or semiclosed environmental system. The apparatus takes...

Briefs: Materials
A Technique for Injecting Ag+ Ions as Biocide into H2O

A simple and reliable technique facilitates the addition of silver ions to water supplies to suppress bacterial contamination. In the original application for which the technique was devised, there is a need for Ag+-ion concentrations at a biocidal levels (0.5 mg/L) in 44-L...

Briefs: Materials
Experiments on Residual-Stress Bondline Failures in an RSRM

A report describes an experimental study undertaken to verify a finite-element mathematical model used to predict residual stresses and stress-induced failures in the adhesive interfacial layers (bondlines) that join phenolic liners to interior surfaces of metal housings of...

Briefs: Materials

Latently reactive end caps have been investigated as improved means to increase the thermo-oxidative stability of polyimides of the polymerization of monomeric reactants (PMR) type,...

Briefs: Materials

An additional class of end-cap compounds that increase the thermo-oxidative stability of polyimides of the polymerization of monomeric reactants (PMR) type has been invented. The...

Briefs: Materials

Low-density, ablative thermal-protection panels can be made by impregnating fibrous ceramic substrates with organic polymers. With proper design and fabrication, these panels can...

Briefs: Materials
Solar Heating for Deployment of Foam Structures

Solar heating has been proposed as a means of deployment of structures of the type described in "Cold Hibernated Elastic Memory (CHEM) Expandable Structures," (NPO-20394), NASA Tech Briefs, Vol. 23, No. 2 (February 1999), page 56. A few examples of structures that would be amenable to the CHEM...

Briefs: Materials
Fluorinated Diamondlike Carbon Coatings

Some experiments directed toward the development of improved hard, lubricious coating materials have involved direct fluorination of proprietary diamondlike coats on various substrates. The idea is to retain the hardness of the diamondlike material while adding surface molecular structures that impart the...

Briefs: Materials
Solar Sails Would Be Made From Carbon Nets

A report proposes that solar sails for spacecraft be made from nets of carbon fibers. The reason for choosing carbon nets over thin polymeric films is that nets offer greater capability for carrying tensile loads. The sails could be made from carbon-fiber nets of various thicknesses: nets used for...

Briefs: Materials
Solar Sails Would Be Segmented To Minimize Stresses

A report proposes that solar sails for spacecraft be constructed in segments in such a way as to minimize stresses. The segments could be made of metallized fabric or film and could be connected by short, strong tethers. Alternatively, the segments could be like islands, held loosely in...

Briefs: Materials

A methodology for predicting stresses and the resultant cracking in plasma-sprayed thermal-barrier coatings (TBCs) has been developed. The methodology is built around a computer code that...

Briefs: Materials

Experiments have shown that ultrasound could be an effective means of enhancing the removal of chlorinated hydrocarbon contaminants from groundwater by the zero-valent-metal treatment...

Briefs: Materials
Multi-Shock Blankets for Protecting Spacecraft

A report discusses multi-shock blankets, which are under investigation for use in protecting spacecraft against orbiting debris from prior spacecraft missions. Multi-shock blankets are described in comparison with early protective metallic "bumpers" and with a somewhat more recent invention called...

Briefs: Materials
Study of High-Performance Polyimide Foams

This report describes an experimental study of thermal-stability, mechanical, and flammability properties of foams of several different densities made of three different polyimides. The study was performed because (1) prior such studies were performed on polyimide films rather than foams and (2)...

Briefs: Materials

Compression Stress Relaxation (CSR) is an important factor in evaluating elastomer materials and seal configurations for their ability to provide sealing force retention under...

Briefs: Materials
Making Ion-Accelerator Grids From Ti Instead of Mo

Titanium has been found to offer several advantages over molybdenum as the material used to construct electrostatic-accelerator and -screen grids for ion thrusters for spacecraft. These advantages could also be expected to extend to the manufacture of grids for ion accelerators used in...

Briefs: Materials
Thermal Insulation Would Use CO2 in the Martian Environment

A report describes the development of a lightweight thermal insulation system for Martian surface applications. The ambient Martian atmosphere, which is predominantly carbon dioxide at a pressure of 10 torr, is used as the insulation medium with a modest multiple radiation shield...

Briefs: Materials

Filled skutterudites have shown promise as semiconducting materials with superior thermoelectric properties at temperatures up to at least 650 °C. This finding is a breakthrough in a...

Briefs: Materials

Alkoxides of lithium have been found to be useful as electrolyte additives to improve the low-temperature performance of rechargeable lithium-ion electrochemical cells. As...

Briefs: Materials

Aliphatic esters have been found to be useful as electrolyte additives for improving the low-temperature performances of rechargeable lithium-ion electrochemical cells. The...

Briefs: Materials

Ethyl methyl carbonate (EMC) has been found to be a suitable cosolvent, along with three other carbonate solvents, for incorporation into electrolytes to enhance the low-temperature...

Briefs: Materials

Titanium disulfide has been found to be attractive as an alternative to graphite as the anode material in rechargeable lithium-ion electrochemical cells that are required to operate at...

Briefs: Materials

Liquid and paste polyorganosiloxane formulations (which become high-temperature- and oxidation-resistant organosilicone-based ceramics upon curing) have been invented for use in (1)...

Briefs: Materials
Polyorganosiloxane Waterproofing for Porous Ceramics

Liquid waterproofing agents based on polyorganosiloxanes have been invented for use in treating porous, lightweight, fibrous ceramic thermal-insulation materials in both tile (rigid) and blanket (flexible) forms. Whereas silane-based waterproofing materials developed previously for this...

Briefs: Materials

A technique for holding sensor lead wires in place on substrates made of SiC-based monolithic ceramic or SiC/SiC fiber-reinforced ceramic-matrix composite materials involves...

Briefs: Materials
Improved Polymeric Composite Materials for Dental Fillings

Composite materials that include combinations of metal oxide and silica nanoparticles in polymeric matrices have been invented for primary use as dental fillings, dental and bone adhesives, and the like. There have been previous efforts to develop polymeric replacements for the amalgam...

Briefs: Materials

A thin polymer/metal laminate has been developed for use as an envelope material for lightweight heat pipes and heat-pipe radiators that operate at temperatures up to 360 K. The...

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