Device for measurement the seebeck coefficient of thermoelectric materials in the temperature range 300-800â¯K

The determination of the potential characteristics of new thermoelectric materials from the results of measurements of the Seebeck coefficient is described. A device has been developed for measuring the Seebeck coefficient (thermoelectric motive force) of thermoelectric materials in the temperature range 300-800â¯K in argon, air, or vacuum. The design and technical characteristics of the created device are described in detail. The Seebeck coefficient of standard nickel samples in the temperature range of 300-800â¯K in an argon medium was measured in order to verify the applicability of the developed device by the differential method. Measurement error of the Seebeck coefficient is less than 5%. Negative values of the Seebeck coefficient of the nickel sample were obtained throughout the studied temperature range, which indicates the predominance of electrons as the main charge carriers in the sample material. At room temperature, the measured value of the Seebeck coefficient is -19.05â¯[mu]V/K and decreases to a value of -25.71â¯[mu]V/K as the temperature increases to 515â¯K. As the temperature increases further to 640â¯K, the Seebeck coefficient monotonically increases to a value of -19.60â¯[mu]V/K. At temperatures above 640â¯K, the Seebeck coefficient decreases continuously, and at 824â¯k reaches the value -24.12â¯[mu]V/K. The Curie point is 644â¯K. The values of the Seebeck coefficient for nickel that are obtained in the temperature range 300-800â¯K are comparable with the data given in the literature. In calculating the values of the Seebeck coefficient based on measured thermoelectric voltages, equations with known reference values of this coefficient for positive and negative branches of the thermocouple are used, which eliminates the need for additional measurement probes and contacts to measure the thermoelectric voltage of a sample. The installation can also be used to measure electrical resistance using the standard 4âpoint method.