scholarly journals Dependence of Thermal and Electrical Conductivities of Actinide-Zirconium-Hydride Composite Materials on Hydrogen Concentration

10.5772/14584 ◽  
2011 ◽  
Author(s):  
B. Tsuchiya ◽  
K. Konashi ◽  
M. Yamawaki
Keyword(s):  
Composite Materials ◽  
Hydrogen Concentration ◽  
Zirconium Hydride ◽  
Electrical Conductivities

Effect of partial filling of the structural vacant sites on the thermoelectric properties of Zr0.25Hf0.75NiSn half-Heusler alloy

2010 ◽  
Vol 1267 ◽  
Author(s):  
Julien Pierre Amelie Makongo Mangan ◽  
Dinesh Misra ◽  
Nathan J. Takas ◽  
Kevin L. Stokes ◽  
Heike Gabrisch ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
Composite Materials ◽  
Solid State ◽  
Solid State Reaction ◽  
Lattice Thermal Conductivity ◽  
Strong Reduction ◽  
Partial Filling ◽  
Electrical Conductivities ◽  
Spark Plasma ◽  
Full Heusler

AbstractComposites containing mainly-half-Heusler MNiSn (HH) and full-Heusler MNi2Sn (FH) were prepared by solid state reaction of a mixture of polycrystalline bulk HH alloy with various concentrations of Ni up to 10 wt.%. Electrical conductivities, thermal conductivities and thermopowers of spark plasma sintered specimens of the as synthesized composite materials were measured in the temperature range from 300 K to 750 K. The conduction type of the composite changes from semiconductor to semimetal for Ni concentrations up to 2 wt.% and from semimetal to metal for higher Ni concentrations above 5 wt.%. A strong reduction in lattice thermal conductivity was observed for the composite containing 10 wt. % Ni inclusions.

Composites Based on Thermoplastic Polymeric Matrix and Carbon Nanoparticles with Special Functional Properties

2019 ◽  
Vol 816 ◽  
pp. 244-249
Author(s):  
Olga A. Moskalyuk ◽  
E.S. Tsokkallo ◽  
A.S. Stepashkina ◽  
V.E. Yudin
Keyword(s):  
Electrical Conductivity ◽  
Composite Materials ◽  
Carbon Black ◽  
Polymer Composite ◽  
Carbon Nanoparticles ◽  
Spherical Particles ◽  
Anisotropic Nanoparticles ◽  
Electrical Conductivities ◽  
Polypropylene Matrix ◽  
Carbon Nanofillers

Polymer composite materials based on polypropylene matrix and carbon nanoparticles of various shapes: spherical particles - carbon black and anisotropic nanoparticles - carbon nanofibers, were obtained by the melt technology. A character of the dependences of the electrical conductivities on the concentration of carbon nanofillers has been revealed. A simulation of the electrical conductivity of the polymer composite in the region of the concentration of the filler at the threshold of the flow of electric current and below it was carried out.

Electrically conductive composites via infiltration of single-walled carbon nanotube-based aerogels

2010 ◽  
Vol 1258 ◽  
Author(s):  
Marcus A Worsley ◽  
Joshua D. Kuntz ◽  
Sergei Kucheyev ◽  
Alex V Hamza ◽  
Joe H Satcher ◽  
...  
Keyword(s):  
Carbon Nanotubes ◽  
Electrical Conductivity ◽  
Carbon Nanotube ◽  
Composite Materials ◽  
Low Density ◽  
Electrically Conductive ◽  
Single Walled Carbon Nanotube ◽  
Insulating Materials ◽  
Conductive Composites ◽  
Electrical Conductivities

AbstractMany challenges remain in the effort to realize the exceptional properties of carbon nanotubes (CNT) in composite materials. Here, we report on electrically conductive composites fabricated via infiltration of CNT-based aerogels. The ultra low-density, high conductivity, and extraordinary robustness of the CNT aerogels make them ideal scaffolds around which to create conductive composites. Infiltrating the aerogels with various insulating materials (e.g. epoxy and silica) resulted in composites with electrical conductivities over 1 Scm-1 with as little as 1 vol% nanotube content. The electrical conductivity observed in the composites was remarkably close to that of the CNT scaffold in all cases.

Comparative Microstructures of Ion Milled and Electrochemically Thinned Composite Materials

1974 ◽  
Vol 32 ◽  
pp. 546-547
Author(s):  
R.R. Russell
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Composite Materials ◽  
Great Difficulty ◽  
Ion Milling ◽  
Transmission Electron ◽  
Ion Damage ◽  
Intermetallic Composite

Transmission electron microscopy of metallic/intermetallic composite materials is most challenging since the microscopist typically has great difficulty preparing specimens with uniform electron thin areas in adjacent phases. The application of ion milling for thinning foils from such materials has been quite effective. Although composite specimens prepared by ion milling have yielded much microstructural information, this technique has some inherent drawbacks such as the possible generation of ion damage near sample surfaces.

Transmission electron microscopy of composite materials

1988 ◽  
Vol 46 ◽  
pp. 1012-1015
Author(s):  
K.P.D. Lagerlof
Keyword(s):  
Composite Materials ◽  
Physical Properties ◽  
Structural Defects ◽  
Structural Composites ◽  
Multiphase Materials ◽  
Structural Reinforcement ◽  
Transmission Electron ◽  
Reinforced Fiber ◽  
Particulate Reinforced Composites ◽  
Definition Of

Although most materials contain more than one phase, and thus are multiphase materials, the definition of composite materials is commonly used to describe those materials containing more than one phase deliberately added to obtain certain desired physical properties. Composite materials are often classified according to their application, i.e. structural composites and electronic composites, but may also be classified according to the type of compounds making up the composite, i.e. metal/ceramic, ceramic/ceramie and metal/semiconductor composites. For structural composites it is also common to refer to the type of structural reinforcement; whisker-reinforced, fiber-reinforced, or particulate reinforced composites [1-4].For all types of composite materials, it is of fundamental importance to understand the relationship between the microstructure and the observed physical properties, and it is therefore vital to properly characterize the microstructure. The interfaces separating the different phases comprising the composite are of particular interest to understand. In structural composites the interface is often the weakest part, where fracture will nucleate, and in electronic composites structural defects at or near the interface will affect the critical electronic properties.

Evidence for a shear mechanism for the precipitation of γ-zirconium hydride in zirconium

1978 ◽  
Vol 36 (1) ◽  
pp. 658-659
Author(s):  
G.J.C. Carpenter
Keyword(s):  
Elevated Temperature ◽  
Strain Field ◽  
Zirconium Hydride ◽  
Zirconium Atom ◽  
Atom Diffusion ◽  
Solvus Temperature ◽  
Hexagonal Close Packed ◽  
Partial Dislocations ◽  
The Face

In zirconium-hydrogen alloys, rapid cooling from an elevated temperature causes precipitation of the face-centred tetragonal (fct) phase, γZrH, in the form of needles, parallel to the close-packed <1120>zr directions (1). With low hydrogen concentrations, the hydride solvus is sufficiently low that zirconium atom diffusion cannot occur. For example, with 6 μg/g hydrogen, the solvus temperature is approximately 370 K (2), at which only the hydrogen diffuses readily. Shears are therefore necessary to produce the crystallographic transformation from hexagonal close-packed (hep) zirconium to fct hydride.The simplest mechanism for the transformation is the passage of Shockley partial dislocations having Burgers vectors (b) of the type 1/3<0110> on every second (0001)Zr plane. If the partial dislocations are in the form of loops with the same b, the crosssection of a hydride precipitate will be as shown in fig.1. A consequence of this type of transformation is that a cumulative shear, S, is produced that leads to a strain field in the surrounding zirconium matrix, as illustrated in fig.2a.

Electronic structure studies of conducting polymers by electron energy-loss spectroscopy

1996 ◽  
Vol 54 ◽  
pp. 160-161
Author(s):  
J. Fink
Keyword(s):  
Electronic Structure ◽  
Conducting Polymers ◽  
Conjugated Polymers ◽  
Electron Acceptors ◽  
Electron Donors ◽  
Light Emitting ◽  
One Dimensional ◽  
New Class ◽  
Electrical Conductivities ◽  
Electron Energy Loss

Conducting polymers comprises a new class of materials achieving electrical conductivities which rival those of the best metals. The parent compounds (conjugated polymers) are quasi-one-dimensional semiconductors. These polymers can be doped by electron acceptors or electron donors. The prototype of these materials is polyacetylene (PA). There are various other conjugated polymers such as polyparaphenylene, polyphenylenevinylene, polypoyrrole or polythiophene. The doped systems, i.e. the conducting polymers, have intersting potential technological applications such as replacement of conventional metals in electronic shielding and antistatic equipment, rechargable batteries, and flexible light emitting diodes.Although these systems have been investigated almost 20 years, the electronic structure of the doped metallic systems is not clear and even the reason for the gap in undoped semiconducting systems is under discussion.

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