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Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

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At least 847 records · Page 47
All sourcesNASA NTRSDOE OSTI
NASA NTRS1972

A new vibration dampening adhesive

Formulation of polymers has been devised that, when vibrated, adhesive becomes more fluid (thixotropic) to better absorb shock and, when warmed, will actually hold its shape better (thermosetting) rather than deform.

Yoshino, S. Y.↗
NASA NTRS1972

Adhesion and transfer of PTFE to metals studied by auger emission spectroscopy

The adhesion and transfer of polytetrafluoroethylene (PTFE) to metals in ultrahigh vacuum has been studied using Auger emission spectroscopy. The transfer was effected both by compressive static contact and by sliding contact. The transfer observed after static contact was independent of the chemical constitution of the substrate. Electron induced desorption of the fluorine in the transferred PTFE showed that the fluorine had no chemical interaction with the metal substrate. The coefficient of friction on metals was independent of the chemical constitution of the substrate. However, sliding PTFE on soft metals such as aluminum, generated wear fragments that lodged in the PTFE and machined the substrate.

Pepper, S. V.↗
NASA NTRS1972

Adhesion and transfer of polytetrafluorethylene to metals studied by Auger emission spectroscopy

The adhesion and transfer of polytetrafluoroethylene (PTFE) to metals in ultrahigh vacuum were studied. The transfer was effected both by compressive static contact and by sliding contact. The transfer observed after static contact was independent of the chemical constitution of the substrate. Electron-induced desorption of the fluorine in the transferred PTFE showed that the fluorine had no chemical interaction with the metal substrate. The coefficient of friction on metals was independent of the chemical constitution of the substrate. However, sliding PTFE on soft metals, such as aluminum, generated wear fragments that lodged in the PTFE and machined the substrate.

Pepper, S. V.↗
NASA NTRS1973

Semi-organic structural adhesive for aluminum

Structural adhesive consists of titanium chelate polymer, reactive plasticizer, and cure accelerator (phenylsilanetriol). Mixture polymerizes in situ in 65 hours at 170 C.

Kwan, S. C.↗
NASA NTRS1973

Chemistry technology: Adhesives and plastics: A compilation

Technical information on chemical formulations for improving and/or producing adhesives is presented. Data are also reported on polymeric plastics with special characteristics or those plastics that were produced by innovative means.

Source record↗
NASA NTRS1973

An adhesion criterion in the gas solid interface

A theoretical model is developed to establish an adhesion criterion for the interaction of a gas atom or molecule with a nonmetallic surface. As a first approximation a linear lattice mass points of the solid surface is considered and the classical lattice dynamical model is used.

George, M. C.↗
NASA NTRS1974

Adhesion, friction and Auger spectroscopy analysis of a commercial cobalt base aircraft turbine shroud alloy

A commercially used cast cobalt base alloy was investigated as a turbine shroud material which revealed a surface enriched with tungsten and carbon suggesting a surface layer of tungsten carbide. Adhesion and friction of this segregated surface layer are higher than for the bulk cobalt base alloy composition. Auger spectroscopy analysis of the segregation of tungsten in the alloy indicates that it occurs between 850 and 1000 C.

Buckley, D. H.↗
NASA NTRS1974

The atomic nature of polymer-metal interactions in adhesion, friction and wear

The adhesion, friction, and wear behavior of the solid polymers PTFE and polyimide in contact with various metals were studied using field ion microscopy, Auger emission spectroscopy, and scanning electron microscopy. Results indicate that the polymers will transfer to a clean tungsten surface on simple tough contact, forming a chemical bond. With PTFE, it is hypothesized that the bonding is of the carbon to the metal surface, while with the polyimide, both oxygen and carbon bonding to the tungsten surface are possible. In sliding contact, the friction process itself can initiate polymer film formation. The formation of such films has been suggested as a form of extreme pressure lubrication.

Buckley, D. H.↗
NASA NTRS1975

Process for preparing polyimide adhesives

High bonding strengths are obtained for metals and fiber-reinforced organic resin composites with no significant loss in thermo-oxidative stability of the adhesive resin.

Progar, D. J.↗
NASA NTRS1974

Mixed mode stress field effect in adhesive fracture

Numerical or analytical analyses were performed on seven different test specimens including blister test, 90-degree peel test, torsion test, and various cone tests. These specimens are in general subjected to complex stress fields having various amounts of Mode I, Mode II, and Mode III loads. The specimens were then constructed using polymethyl methacrylate for the adherends and a transparent polyurethane elastomer (Solithane 113) for the adhesive. This combination permitted direct observation of the bondline as load was applied. Although initial debonds as well as bond end termination singularities were present in all specimens, in some cases the debond did not initiate at the singularity points as would normally have been expected. An explanation for this behavior is presented, as well as a comparison of loading mode effect on those specimens for which the debond did propagate from a bond terminus singular point.

Anderson, G. P.↗
NASA NTRS1976

Polymer adhesives for hybrid circuits

Report discusses number of tests used in comparing polymer adhesives with metal bonding processes and includes charts and photographs to illustrate test results. Findings suggest reduced quality control costs when epoxies are used in fabrication of microcircuits.

Caruso, S. V.↗