University of California

The United States of America As Represented by the United States

Los Alamos National Security, LLC

The United States of America As Represented by the Department of Energy

Dean E Peterson

Yuntian Theodore Zhu

Quanxi Jia

John F Bingert

Huisheng Peng

Kevin Curtis Ott

Terry G Holesinger

Richard B Cass

William Larry Hults

Kenneth V Salazar

Haskell Sheinberg

David S Phillips

Xiao Zhou Liao

David A Korzekwa

Adriana C Serquis

Patrick S Baldonado

Frederick M Mueller

Kimberly A Kubat-Martin

Fibrous composite comprising a plurality of carbon nanotubes; and a silica-containing moiety having one of the structures: (SiO)Si&#x2014;(CH)&#x2014;NRR) or (SiO)Si&#x2014;(CH)&#x2014;NCO; where n is from 1 to 6, and Rand Rare each independently H, CH, or CH.

Fibrous composites comprising carbon nanotubes and silica

A carbon microtube comprising a hollow, substantially tubular structure having a porous wall, wherein the microtube has a diameter of from about 10 &#x3bc;m to about 150 &#x3bc;m, and a density of less than 20 mg/cm. Also described is a carbon microtube, having a diameter of at least 10 &#x3bc;m and comprising a hollow, substantially tubular structure having a porous wall, wherein the porous wall comprises a plurality of voids, said voids substantially parallel to the length of the microtube, and defined by an inner surface, an outer surface, and a shared surface separating two adjacent voids.

Carbon microtubes

A process of preparing superconducting magnesium diboride powder by heating an admixture of solid magnesium and amorphous boron powder or pellet under an inert atmosphere in a Mg:B ratio of greater than about 0.6:1 at temperatures and for time sufficient to form said superconducting magnesium diboride. The process can further include exposure to residual oxygen at high synthesis temperatures followed by slow cooling. In the cooling process oxygen atoms dissolved into MgB segregated to form nanometer-sized coherent Mg(B,O) precipitates in the MgB matrix, which can act as flux pinning centers.

Synthesis of magnesium diboride by magnesium vapor infiltration process (MVIP)

Superconductor tapes are annealed under uniaxial pressure, such a compressive annealing yielding significant improvement in the resultant critical current density. This thermomechanical processing technique obtains improved critical currents with fewer processing steps.

Compressive annealing of superconductive tapes

A superconductive article is made by inserting a rigid mandrel into an internal cavity of a first metallic tube, said tube having an interior surface and an exterior surface, said interior surface defining the interior cavity, forming a layer of a superconductive material or superconductive precursor upon the exterior surface of said first metallic tube, machining the layer of superconductive material or superconductive precursor to a predetermined diameter to form an intermediate article configured for insertion into a second metallic tube having an interior diameter corresponding to the predetermined diameter, inserting the machined intermediate article into a second metallic tube having an internal diameter corresponding to the predetermined diameter of the intermediate article to form a composite intermediate article, reducing or ironing the composite intermediate article to a predetermined cross-sectional diameter, and sintering the reduced or ironed composite intermediate article at temperatures and for time sufficient for the superconductive material or superconductive precursor to exhibit superconductivity.

Superconductive wire

A process and a precursor composition for preparing a lead-doped bismuth-strontium-calcium-copper oxide superconductor of the formula Bi.sub.a Pb.sub.b Sr.sub.c Ca.sub.d Cu.sub.e O.sub.f wherein a is from about 1.7 to about 1.9, b is from about 0.3 to about 0.45, c is from about 1.6 to about 2.2, d is from about 1.6 to about 2.2, e is from about 2.97 to about 3.2 and f is 10.+-.z by reacting a mixture of Bi.sub.4 Sr.sub.3 Ca.sub.3 Cu.sub.4 O.sub.16.+-.z, an alkaline earth metal cuprate, e.g., Sr.sub.9 Ca.sub.5 Cu.sub.24 O.sub.41, and an alkaline earth metal plumbate, e.g., Ca.sub.2-x Sr.sub.x PbO.sub.4 wherein x is about 0.5, is disclosed.

Synthesis of BiPbSrCaCuO superconductor

A process for fabricating superconducting composite wire by the steps of placing a superconductive precursor admixture capable of undergoing a self propagating combustion in stoichiometric amounts sufficient to form a superconductive product within a metal tube, sealing one end of said tube, igniting said superconductive precursor admixture whereby said superconductive precursor admixture endburns along the length of the admixture, and cross-section reducing said tube at a rate substantially equal to the rate of burning of said superconductive precursor admixture and at a point substantially planar with the burnfront of the superconductive precursor mixture, whereby a clad superconductive product is formed in situ, the product characterized as superconductive without a subsequent sintering stage, is disclosed.

Process for producing clad superconductive materials

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Los Alamos, NM, United States of America

Dean E Peterson