Abstract – Thermoelectric properties of the PbS ZnS…
We present the results of investigations on the thermoelectric properties of the PbS ZnS alloy semiconductor.Homogeneous pallet crystals of PbS ZnS alloy of composition 50% PbS + 50% ZnS were made by compression of a good mixture of fine powder of natural PbS and ZnS ore minerals from Ishiagu in the Imo State of Nigeria. The electrical and thermal conductivities, Seebeck coefficient and I2R (Joule’s) losses for the samples were studied.Two sets of samples were investigated. The first set was fabricated at the same sintering pressure of 70 kN/cm2 and annealed in air for 1 h each at different temperatures, while the second set was fabricated at different sintering pressures and then annealed in air at the same temperature of 500°C. For both sets of samples, the electrical conductivity was found to increase nonlinearly with an increase in temperature. At temperature’s beyond 360 K, the relationship between electrical conductivity and temperature becomes linear.On the other hand, the relationship between thermal conductivity and annealing temperature is very irregular. The same irregular relationship was obtained for the variation of the steady-state Seebeck coefficient with annealing temperature. For pallets annealed at different temperatures, however, the Seebeck coefficient and I2R loss were found to increase nonlinearly as the temperature difference increases [where temperature difference is the difference between the temperature of the reference (cold end of the sample) and the hot end]. For the sample annealed at 200°C, however, the relationship between the Seebeck coefficient and temperature difference is linear for a considerable range of temperature, while in all cases, the I2R loss is very low (10−8 J), and its variation with temperature beyond 310 K is linear.
Energy Conversion and Management 03/1992; 33(3):159-164. DOI:10.1016/0196-8904(92)90121-C