High Temperature Thermoelectric Research

This paper presents information concerning applied research on promising new high temperature thermoelectric materials capable of operation to at least 1200°C*. Included are discussions of the basic materials characteristics, research conducted to obtain usable thermoelements, sublimation information, experimental model test data, and advanced thermoelectric components research. The basic thermoelectric materials are designated MCC 50**, p-type for 500-1200°C operation; MCC 60, n-type for 700-1200°C operation; and MCC 40, both p- and n-type for use to 950°C operation. Results of two years of effort include: (1) successful formation of contact junctions to MCC 40, 50, and 60; (2) successful fabrication and utilization of segmented p-n thermocouples; (3) 1000-hour sublimation and diffusion tests of individual elements and segmented p-n couples at temperature, which indicated no degradation of power producing capabilities; (4) 2500-hour evaluation of MCC 50 elements in a 5-watt experimental model with no degradation; (5) fabrication and preliminary evaluation of a 50-watt laboratory model using segmented p-n couples; and (6) promising results when using arc-plasma and flame-spray techniques for forming thermoelectric components.