PbBi/sub 2/Te/sub 4/ and PbBi/sub 4/Te/sub 7/, thermoelectric materials in the system of Pb-Bi-Te

In order to develop new high performance thermoelectric refrigeration materials, attempt of synthesizing new ternary compounds in M-Bi-Te (M=Zn, Cd, Hg, Ga, In, Ti, V, Nb, Ta, Fe, Ni) systems and evaluation of thermoelectric properties of PbBi/sub 2/Te/sub 4/ and PbBi/sub 4/Te/sub 7/ have been carried out. At first, synthesis of new ternary compounds in the M-Bi-Te systems has been attempted. However, no new ternary chalcogenide has been synthesized in these systems in our synthesis conditions. Secondly, the Pb-Bi-Te system has been investigated and the preparation conditions of PbBi/sub 2/Te/sub 4/ and PbBi/sub 4/Te/sub 7/ have been established. Pellets of these compounds have been prepared and the Seebeck coefficient, the electric conductivity, and the thermal conductivity have been measured, and the figure of merit has been calculated.