A gold-platinum thermocouple

Summary

Since the homogeneity of gold is much higher than that of platinorhodium, the gold-platinum thermocouples provide considerably more accurate temperature measurements than platinorhodium-platinum thermocouples. The high degree of homogeneity of gold is especially valuable when small temperature differences are measured. Another important advantage of the gold-platinum thermocouples as compared with the platinorhodium-platinum ones is their higher thermal emf and lower electrical resistance. The defects of the new thermocouple are its high thermal conductivity, tendency to acquire plastic strains and the low melting point of gold as compared with platinorhodium. These defects are absent in another thermocouple made of pure metals, the rhodium-platinum thermocouple, which we propose to analyse in the future.