The thermoelectric power of titanium carbide

The thermoelectric power of titanium carbide

Solid State Communications Abstracts Vol. 2, pp. viii-x, 1964. Pergamon Press, “J. Phys. Chem. Solids (to be published)” should 3. be cite...

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Solid State Communications

Abstracts

Vol.

2, pp. viii-x,

1964. Pergamon

Press,

“J.

Phys. Chem.

Solids

(to be published)”

should

3.

be cited prior to

ELASTIC CONSTANTS AND LATTICE VIBRATION FREQUENCIES OF Mg2Si.P W. B. Whittens, P. L. Chung and G. C. Danielson (Institute for Atomic Research and Department of Physics, Iowa State University, Ames, Iowa, U.S. A. ).

The longitudinal and transverse sound velocities of Mg2Si in the [llO] and [ill] directions have been measured from 800 to 3000K by a resonance technique. The elastic constants obtained from these velocities were combined with optical data to calculate the lattice vibration frequencies and specific heat for a point charge model. The calculated and experimental specific heats were compared. The Debye temperatures have the same general temperature dependence, but the calculated values are about 5 per cent higher than the experimental values.

PHASE TRANSFORMATIONS IN SOLID CYCLOHEXANOL.+ J. R. Green and W. T. Griffith (The University of New Mexico, Albuquerque, New Mexico, U. S. A. ).

Relations between the three forms of solid cyclohexanol that are encountered from the melting point down to liquid nitrogen temperatures have been investigated by capacitative measurements. This is possible because of the abnormally high dielectric constant of the form that exhibits rotation in the solid state. The kinetics of the phase transformations from the rotational solid form to the non-rotational forms have been followed in detail in the temperature region from - 200C to - 6OoC, and comparison has been made with the theory due to Avrami. The characteristic times for the transformations

(Received 29 April 1964) (Revised 6 July 1964) 4.

PARAMAGNETISCHE E LEKTRONENRESONANZ, ELEKTRISCHE LEITFAHIGKEIT UND FREMDSTOFFDIFFUSION IN BOR. D. Geist and H. J. GHiser (II. Physikalisches Institut, Universitat zu K&i, Germany). In larger

* +

of the

in this region exhibit a regular but not a simple behavior that is interpreted in terms of competing transformations to the two non-rotational solid forms. (Received 9 March 1964) (Revised 2 July 1964)

THE THERMOELECTRIC POWER OF TITANIUM CARBIDE.* R. G. Lye (Union Carbide Corporation, Carbon Products Division, Research Laboratory, Parma, Ohio, U. S. A. ).

The thermoelectric power of TiC is shown to depend on composition in a way which is not consistent with the earlier discussion of Noguchi and Sato. The behavior can be interpreted, however, in terms of the model proposed by Mott for the transition metals, i. e. transport in a single s-band whose electrons have a mean free time determined by scattering by carbon vacancies into empty states in an overlapping d-band. (Received 2 July 1964)

2.

in the United States

of Articles to be Published in the Journal Physics and Chemistry of Solids in references to material quoted from this section the publication of the relevant article.

1.

Inc. Printed

This work was supported in part by U. S. Air Force Contract No. AF 33(657)-10109. This work has been sponsored by Sandia Corp., a prime contractor to the A. E. C., by the N. S. F. and by the University Research Committee of the University of New Mexico.

concentrations

numerous

im-

Ir Contribution No. 1433. Work was performed in the Ames Laboratory of the U.S. A. E. C. § Present address: Department of Physics, University of Sao Paulo, Sao Paulo, Brazil. ..

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