Title

Excitation Processes In Ceramics And The Anomalous Increase In Thermal Conductivity At Elevated Temperatures

Date

1962

Index Abstract

Contrails and DTIC

Photo Quality

Not Needed

Report Number

WADD TR 60-866

Corporate Author

Wright Air Development Division

Laboratory

Materials Central

Extent

16

Identifier

AD0285283

AD0285283

Access Rights

OTS

Distribution Classification

1

Contract

AF 33(616)-6194

DoD Project

7022

DoD Task

73664

DTIC Record Exists

Yes

Distribution Change Authority Correspondence

None

Abstract

The problem of the anomalous increase in the observed thermal conductivity of single-phase ceramics at high temperatures has been considered. At temperatures above the onset of this anomalous rise, account has been taken of the possibility that phonon, electronic, and radiative heat transfer, as well as transport of thermal energy by electron-hole pairs, excitons and dissociated gas molecules, may operate simultaneously and individually contribute significantly to the total heat flow. On the basis of reliable conductivity data on monocrystals of single-phase ceramics, estimations have been made on the magnitudes of these high-temperature components which reveal that excited states of low excitation energy may occur in certain ceramics. In these instances, such excited energy-carrying states are able to diffuse down the temperature gradient in the specimen thereby producing a non-negligible contribution to its observed thermal conductivity.

Report Availability

Full text available

Full text available

Date Issued

1962-07

Subject

Ceramic Materials

Thermal Conductivity

Aluminum Compounds

Calcium Compounds

Crystals

Excitation

Fluorides

Heat Transfer

Oxides

Phonons

Temperature

Thermodynamics

Titanium Compounds

Publisher

Wright-Patterson Air Force Base, OH : Directorate of Materials and Processes, Aeronautical Systems Division, Air Force Systems Command

Distribution Conflict

No

Provenance

Lockheed Martin Missiles & Fire Control

Type

report

Format

1 online resource

Creator

Whitmore, D. H.