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Title: Isotec final report

Technical Report ·
DOI:https://doi.org/10.2172/5437033· OSTI ID:5437033

General Atomic (GA) developed processes to prepare NdSe/sub 1.5-x/. The partial pressure of Se/sub 2/ above the NdSe/sub 1.5-x/ was found to be a function of x. The thermoelectric properties and the friability of the hot pressed element were also a function of x. Process modification changed the value of x, providing a method to control the properties of N-type NdSe/sub 1.5-x/ elements. A method of joining NdSe/sub 1.5-x/ to a nickel hot cap was developed using a gold foil intermediate. NdSe/sub 1.5-x/ was diffusion-bonded to PbTe by the same process developed for Gd/sub 2/Se/sub 3/. Couples were fabricated from (Cu,Ag)/sub 2/Se/Fe/(Bi,Sb)/sub 2/Te/sub 3/ and NdSe/sub 1.5-x/ PbTe elements. Limited couple test data were obtained. General Atomic examined methods to develop high-efficiency couples made from segmented elements containing (Cu,Ag)/sub 2/Se P-type material and NdSe/sub 1.5-x/ N-type material. Techniques were developed to reproducibly prepare and hot press (Cu,Ag)/sub 2/Se segments and elements with a metallurgically joined MoRe hot cap. This hot cap and a W-26/Re wire mesh used to make the hot cap junction were found to be stable in contact with (Cu,Ag)/sub 2/Se at 750/sup 0/C. Stability of (Cu,Ag)/sub 2/Se to current flow in a thermal gradient was examined. This report describes specifications for vapor suppression to improve the stability of P-type (Cu,Ag)/sub 2/Se in thermal gradient life tests and presents life test information on match-loaded (Cu,Ag)/sub 2/Se and (Cu,Ag)/sub 2/Se/Fe/(Bi,Sb)/sub 2/Te/sub 3/ elements.

Research Organization:
General Atomics, San Diego, CA (United States)
DOE Contract Number:
AT03-76ET33004
OSTI ID:
5437033
Report Number(s):
GA-A-16584; ON: DE82015077; TRN: 82-013511
Country of Publication:
United States
Language:
English