Designing Apparatus for Highly Precise Measurement of Electrical Conductivity and Seebeck Coefficient from 85 K to 1200 K

Abstract

We describe the development of apparatus for measuring of electrical conductivity and Seebeck coefficient with high precision from 85 K to 1,200 K. Electrical resistance was measured by means of four-point probe method as a function of temperature. The temperature below 400 K was measured by using type T thermocouple in vacuum system was used and from 400 to 1,200 was measured by using Type S was applied for temperature between 400 and 1200 Kelvin in an inert gas system. With the dimensions of the specimen, the electrical resistivity (ρT) can be obtained in the unit of microohm-centimeter (μΩ-cm) and be written in polynomial, ρT=-0.3191+6.8×10-3T-6.0×10-7 T2+8.0×10-10T3. The electrical conductivity can be obtained by taking inversion of the electrical resistivity. Seebeck coefficient (αT ) can be calculated in microvolt per Kelvin as follows: αT=1.9653-1.49×10-2T+9.0×10-5T2-2.0×10-7T3+2.0×10-10T4-1.0×10-13T5+3.0×10-17T6 , when T is temperature in K. The Seebeck coefficient data was compared with X-ray diffraction (XRD) and X-ray fluorescence (XRF) of the specimen. The result showed that our developrd apparatus yields the same as standard method when copper with purity greater than 99 percent was employed.

Simple apparatus to measure Seebeck coefficient up to 900K

“…Iwanaga et al [19] reported a set up which can measure the Seebeck coefficient upto 1000 K but the main complexity lies in the designing of the sample holder and placing the probes in it through drilling. Paul [20] reported a set up for both Seebeck coefficient and electrical resistivity measurement but both the set-up are applicable till 600 K. Budngam et al [21] reported a set-up for measuring very low Seebeck co-efficient for metals for a wide range of temperature (85-1200 K). Gunes et al [22] reported a set up that also features complicated sample probe design with custom made temperature and voltage probes.…”