Accession Number : AD0802214

Title :   ANALYSIS AND EXPERIMENTAL EVALUATION OF AN ULTRA-HIGH TEMPERATURE PYROLYTIC GRAPHITE THERMOCOUPLE.

Descriptive Note : Final rept. May-Nov 65,

Corporate Author : RAYTHEON CO WALTHAM MA RESEARCH DIV

Personal Author(s) : Klein, C. A. ; Lepie, M. P. ; Donadio, R. N.

Report Date : JUN 1966

Pagination or Media Count : 36

Abstract : This report is made up of three segments as follows: (1) A theoretical analysis of thermoelectricity along graphite layer planes. It is shown how the TEP can be derived from first principles using the Slonczewski-Weiss description of the graphite band structure. From the density of state equation we derive rigorous indications on the energy dependence of the scattering parameter, which allow us to undertake valid comparisons with experimental results. (2) Chapter II summarizes the experimental procedure. Great care was taken in order to arrive at reliable Seebeck coefficients. Thermocouple work was plagued by experimental difficulties (furnace conductance) of a similar nature as experienced by other investigators. (3) Finally, measured TEP was assessed in the light of the theory developed in Chapter I. New light is thus shed upon critical parameters such as the mobility ratio, which leads to a much improved description of transport in pyrolytic graphite and alloys of pyrolytic graphite. It is demonstrated that BPG/PG thermocouples are intrinsically capable of delivering exceptionally favorable output characteristics; a reduction to practice will require further efforts, in particular in connection with proper test-furnace design. (Author)

Descriptors :   *PYROLYTIC GRAPHITE), (*THERMOCOUPLES, HIGH TEMPERATURE, GRAPHITE, THERMOELECTRICITY, SEEBECK EFFECT, MEASURING INSTRUMENTS, WIRING DIAGRAMS, BORON.

Subject Categories : Test Facilities, Equipment and Methods

Distribution Statement : APPROVED FOR PUBLIC RELEASE