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Title: Theoretical-density, integrally bonded thermoelements for SNAP programs. Final report, September 1, 1966--August 31, 1967

Technical Report ·
OSTI ID:4327839

The major aim of this program was to evaluate critically the reproducibility and long-term stability of ductile fine-grained nand p-type metallurgically bonded PbTe thermoelements. Seebeck voltage as a function of temperature was evaluated for a total of 20 n-type and 23 p-type ultrasonically prepared castings. The average deviation of Seeback voltage (at 600 deg C) was determined to be plus or minus 3.9% for n-type and plus or minus 2.4% for p- type castings. Room temperature resistivity measurements were made on 13 n-type and 16 p-type castings. The oxygen content of the thermoelectric material was determined to be less than 3 to 27 ppM for n-type and less than 4 to 20 ppM for p- type. An apparatus for accurate thermal conductivity measurement was designed and constructed. Thermal conductivity as a function of temperature was determined for ptype material. N- and p-type grain-refined castings weighing up to 1 lb were successfully produced using the 2 kW ultrasonic generator and casting unit. The feasibility of ultrasonic casting of n- and p-type thermoelectric material directly from charges of elemental constituents was successfully demonstrated. The fracture strength of the material under compression and tension was measured at room temperature. Compressive strength and deformation for n- and p-type material was 11,410 psi at 11.25% deformation and 12,405 psi at 6.93%, respectively. Tensile strength and deformation were 1,585 psi at 3.99% deformation and .967 psi at 2.78% of deformation. Compressive strength and deformation as a function of temperature was measured. (TFD)

Research Organization:
Tyco Labs., Inc., Waltham, Mass. (USA)
DOE Contract Number:
AT(30-1)-3605
NSA Number:
NSA-29-020783
OSTI ID:
4327839
Resource Relation:
Other Information: Declassified 6 Sep 1973. Orig. Receipt Date: 30-JUN-74
Country of Publication:
United States
Language:
English