The State University of New York

Other

Ucar Carbon Technology Corporation

Deborah D Chung

Yi-Han Kao

Kevin T Fredette

Liwei Song

Xiaoping Shui

Weiming Lu

The present invention relates to strain or stress sensors which include a first planar conductive element, a second planar conductive element, and a flexible graphite sheet sandwiched between the first and second planar conductive elements. The flexible graphite sheet includes a mass of expanded graphite particles compressed together in the absence of a binder. Prior to compression, the expanded graphite particles have a c direction dimension which is at least 80 times that of the graphite particles from which the expanded particles are formed. The sensor is configured so that compression of the sensor causes a change in resistance which can be correlated to strain or stress. The present invention also relates to a strain or stress sensor which includes a polymeric composite, a first electrically conductive lead connected to a first point on or in the polymeric composite, and a second electrically conductive lead connected to a second point on or in the polymeric composite. The polymeric composite includes a polymeric matrix material and carbon filaments having diameters of from about 0.01 .mu.m to about 1.0 .mu.m dispersed therein. Methods for detecting strain or stress are also disclosed.

Methods and sensors for detecting strain and stress

This invention relates to a mesoporous carbon material in the form of filaments having a high surface area. A process is also provided to produce mesoporous carbon material of high surface area. The process comprises drying a carbon material, surface oxidizing the dried material, stabilizing the surface oxidized material, and activating the stabilized material to produce a highly activated, mesoporous material.

Mesoporous activated carbon filaments

A material including filaments, which include a metal and an essentially coaxial core, each filament having a diameter less than 6 .mu.m, each core being essentially carbon, displays high effectiveness for shielding electromagnetic interference (EMI) when dispersed in a matrix to form a composite material. This matrix is selected from the group consisting of polymers, ceramics and polymer-ceramic combinations. This metal is selected from the group consisting of nickel, copper, cobalt, silver, gold, tin, zinc, nickel-based alloys, copper-based alloys, cobalt-based alloys, silver-based alloys, gold-based alloys, tin-based alloys and zinc-based alloys. The incorporation of 7 percent volume of this material in a matrix that is incapable of EMI shielding results in a composite that is substantially equal to copper in EMI shielding effectiveness at 1-2 GHz.

Metal filaments for electromagnetic interference shielding

A new strain/stress sensor based on the concept of reversible crack opening in a composite material. Crack opening increases the electrical resistance, which is the signal provided by the sensor. The new technology is manifested in concrete and mortar containing electrically conducting short fibers (e.g., carbon fibers and steel fibers). Carbon fibers serve to greatly decrease the crack height so that apparently reversible crack opening occurs. The crack opening is accompanied by fiber pull-out, resulting in fiber-matrix contact resistivity increase, thus allowing sensing under cyclic as well as static loading. A part of the resistance change is irreversible, so it provides memory of the first deformation.

Composite material strain/stress sensor

The present invention relates to a particulate carbon complex made from a porous, particulate carbon substrate and a plurality of carbon filaments each having a first end attached to the porous, particulate carbon substrate and a second end distal from substrate. The complex is capable of transferring electrical current at a density of 350 to 10,000 mA/cm.sup.2 for a Fe.sup.+2 /Fe.sup.+3 oxidation/reduction electrochemical reaction couple carried out in an aqueous electrolyte solution containing 6 mM potassium ferrocyanide and 1M potassium nitrate. The complex is prepared by providing a porous, particulate carbon substrate with impregnated metal catalyst and contacting the substrate with a gaseous carbonaceous material under conditions effective to form a plurality of carbon filaments on the substrate. Generally, the complex includes particles of metal catalyst material at the end of the filaments distal from the substrate. The carbon complex is useful in electrochemical applications as well as in structural composites.

Particulate carbon complex

A superconductive fullerene and a process for making such superconductive fullerene are provided. The process involves contacting a quantity of fullerene with the vapor of an interhalogen compound such as ICl. The halogen doped fullerenes exhibited a transition temperature above 60 K.

Inter-halogen-doped superconductive fullerenes

A binder for binding reinforcement materials is provided in which an aluminum and/or Group IIa-containing compound is combined, in a liquid, with a phosphorus-containing compound wherein said binder has a ratio of phosphorus to aluminum and/or Group IIa ions of 14 to 34, preferably 20 to 30. The binder is useful in binding reinforcement materials, particularly suited for preparing preforms for making metal matrix composite materials.

Phosphate binders for metal-matrix composites

A superconductive fullerene and a process for making such superconductive fullerene are provided. The process involves contacting-a quantity of fullerene with the vapor of an interhalogen compound such as ICl. The halogen doped fullerenes exhibited a transition temperature above 60 K.

Halogen-doped superconductive fullerenes

A composite article comprising a resin matrix containing both carbon fibers and a tin alloy. In the preferred embodiment, fiber containing layers within the matrix are separated by alloy containing layers within the matrix. The invention further includes the method of manufacturing the composite articles by impregnating layers of carbon fibers with a resin to form impregnated sheets, spreading alloy powder between the sheets and compression molding the resulting article at a sufficient temperature and pressure for a sufficient time to melt the alloy and cure the resin.

Carbon fiber composites having improved fatigue resistance

A solder joint between two surfaces comprising an intermediate composite solder preform, said preform comprising metal coated carbon fibers contained in a metal matrix, said fibers comprising from 2 to 80 percent by volume of the composite, said metal matrix melting at a temperature below 600.degree. C. and containing at least 15 weight percent tin.

Carbon fiber reinforced tin-lead alloy as a low thermal expansion solder

A superconducting laminate having at least one layer of metal and at least one layer of superconducting material. The metal layer and the superconducting layer are bonded. The metal later may also include carbon fibers from various precursors. The superconductor may be a composite material. The invention also includes a method of making the laminates.

Superconductor-metal laminates and method of making

Portland cement concrete-carbon fiber structure displays high tensile and flexural strengths, low electrical resistivity and high electromagnetic interference shielding effectiveness. The structure comprises cement concrete having a small predetermined proportion of carbon fibers dispersed therein. During the fabrication of the structure, there is added thereto an accelerating admixture comprising polyethanolamine and one of metal sulfate plus metal aluminum sulfate or metal nitrite plus metal chloride. The accelerating admixture comprises a small predetermined weight percentage of the cement in the structure. Additional improvements are obtained by using a small proportion of water-reducing agents.

Carbon fiber reinforced cement concrete composites improved by using

Composites of graphite dispersed in a solid matrix of a polymeric resin, wherein intercalated graphite flakes are mixed with a liquid polymeric resin and exfoliated in-situ in the liquid resin during the curing of the resin before complete solidifcation of the resin.

Composites of in-situ exfoliated graphite

Graphite fibers are exfoliated to produce a fiber of reduced density, increased diameter, and flexibility with respect to graphite fibers prior to exfoliation. The fibers may also be used in composite articles. A method of producing exfoliated graphite fibers intercalates the fibers and then exfoliates the intercalated fiber by heating.

Exfoliated graphite fibers and associated method

This invention relates to composites comprising exfoliated graphite flakes in a polymer matrix which constitutes a small volume fraction; the density of the composite is 0.7 g/cm.sup.3 or below and the electrical resistivity of the composite is 0.5 ohm.cm or below. This invention also relates to composites comprising exfoliated graphite flakes bound by a polymer, such that the flakes are preferentially oriented. In addition, this invention relates to a process for producing these composites.

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Pittsburgh, PA, United States of America

Deborah D Chung