Thermal conductivity and electrical resistivity of cemented carbides, titanium diboride, and high-temperature ceramic superconductors

Miscellaneous · Fri Jan 01 00:00:00 EST 1988

OSTI ID:7224458

Frandsen, M V

The phonon bump in a high-temperature superconductor is here quantitatively analyzed for the first time. The effect is attributable to a factor of two decreases in phonon-electron scattering below as compared to above T{sub c}. Thus, phonon-electron scattering in YBa{sub 2}Cu{sub 3}O{sub 7-x} appears to play a part in lattice thermal resistance even in the superconducting state. The small phonon bump in YBa{sub 2}Cu{sub 3}O{sub 7-x} is to be contrasted with the dramatic rise in lattice thermal conductivity of superconducting NbC{sub x}, which increases two orders of magnitude as NbC{sub x} passes through T{sub c}. In cemented carbides it is found that phonon and electron scattering from defects is the dominant cause of variations in thermal and electrical conductivity above 80{degree}K. Cemented carbides made primarily of nostoichiometric cubic carbides possess a dramatically lower thermal conductivity than WC-based cemented carbides. In high-purity polycrystalline titanium diboride it is found that scattering of phonons and electrons from defects in an important cause of thermal resistivity. The scattering centers are boron vacancies and particles of elemental carbon.

• Research Organization: Illinois Univ., Urbana, IL (USA)
• OSTI ID: 7224458
• Resource Relation: Other Information: Thesis (Ph. D.)
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
CARBIDES
ELECTRIC CONDUCTIVITY
THERMAL CONDUCTIVITY
SUPERCONDUCTORS
TITANIUM BORIDES
BARIUM COMPOUNDS
COPPER COMPOUNDS
CUPRATES
TRANSITION TEMPERATURE
TUNGSTEN CARBIDES
YTTRIUM COMPOUNDS
ALKALINE EARTH METAL COMPOUNDS
BORIDES
BORON COMPOUNDS
CARBON COMPOUNDS
ELECTRICAL PROPERTIES
OXYGEN COMPOUNDS
PHYSICAL PROPERTIES
REFRACTORY METAL COMPOUNDS
THERMODYNAMIC PROPERTIES
TITANIUM COMPOUNDS
TRANSITION ELEMENT COMPOUNDS
TUNGSTEN COMPOUNDS
360204* - Ceramics
Cermets
& Refractories- Physical Properties