International Journal of Thermophysics

, Volume 6, Issue 1, pp 83–99 | Cite as

Changes in seebeck coefficient of Pt and Pt 10% Rh after use to 1700°C in High-purity polycrystalline alumina

  • R. E. Bentley
Article

Abstract

A technique is presented that enables the effects of temperature on the Seebeck coefficient to be assessed for individual wires. The technique, involving a high-resolution thermoelectric scanning rig and a nonuniform conditioning furnace of known temperature profile, was applied to 0.5-mm-diameter wires of Pt and Pt 10% Rh. Changes were observed in Seebeck coefficient when these wires were used in high-purity twin-bore insulation for up to 200 h at temperatures over the range 500 to 1700°C. Contamination from the insulation was found to be transmitted by a vaporization process, having an activation energy of 3 eV. This caused changes of up to 0.14 μV · °C−1 in Pt and 0.01 μV · °C−1 in Pt 10% Rh. Rhodium transfer to the pure Pt wire changed its Seebeck coefficient by up to 5 μV · °C−1. The consequences of both processes for thermocouple pyrometry are presented.

Key words

alumina high temperature platinum Seebeck coefficient thermocouple thermoelectric scanning 

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Copyright information

© Plenum Publishing Corporation 1985

Authors and Affiliations

  • R. E. Bentley
    • 1
  1. 1.CSIRO Division of Applied PhysicsLindfieldAustralia

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