1997 年 9 巻 1-2 号 p. 21-25
The resistivities ρ of the solidified n- and p-type PbTe and plasma activated sintered n-type PbTe were measured as a function of temperature during heating and cooling cycles to progressively higher temperatures until 903K in Ar atmosphere. The hysteresis of the temperature dependence of ρ appeared for all specimens after heated above 703K, which indicates that the change of thermoelectric properties will occur during the operation as a thermoelectric generator. This phenomenon was more remarkable for the sintered specimen than that for the solidified one. However, X-ray analysis did not detect the evidence such as the apperance of the secondary phase or oxidation. Then, it is pointed out that the mechanism of the aging effect for PbTe can not be explained by solely the evaporation of constituents such as Pb, Te and I.
