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oa Thermal Conductivities of Platinum Alloys at High Temperatures
OBSERVATIONS COMPLIANT WITH THE WIEDEMANN-FRANZ RELATION
- Source: Platinum Metals Review, Volume 49, Issue 1, Jan 2005, p. 21 - 26
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- 01 Jan 2005
Abstract
The thermal conductivity of platinum alloys with a f.c.c. single phase was comprehensively surveyed by the laser flash method. Thermal conductivity is predominantly determined by alloy composition and temperature and is little affected by work hardening. An addition of solute clearly decreases the thermal conductivity of Pt, and the conductivity-composition relationship is characterised by a sharp maximum at pure Pt. The Wiedemann-Franz relationship that holds for Pt alloys suggests that the electron is the dominant carrier of thermal conduction. An empirical rule is proposed that the thermal conductivity of a Pt alloy decreases significantly as the position in the Periodic Table of the solute element becomes horizontally more distant from Pt (for the B-subgroup). The thermal conductivity of Pt alloys increases with increasing temperature in the range 300 to 1100 K. The temperature coefficient of thermal conductivity was found to be inversely correlated with the thermal conductivity.