Aluminum substituted for rhodium, which is scarce and expensive. Electromotive force increases with aluminum content in Pt/Al leg of Pt(Pt/Al) thermocouple. Wires baked longer in aluminizing bed produce larger voltages. Thermocouples containing platinum/aluminum legs used instead of thermocouples of type R in furnaces, heat engines, and chemical reactors. Expecially suited to high-velocity oxidizing environments. Constructed as thin-film sensors on turbine blades and vanes, where pre-oxidation provides insulating film needed between thermocouple legs. Because aluminum content slowly depleted by oxidation, long-term use recommended only where maximum temperature is 1,200 degrees C or less.
High-Temperature, Oxidation-Resistant Thermocouples
NASA Tech Briefs ; 18 , 9
1994-09-01
Miscellaneous
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English
High-Temperature, Oxidation-Resistant Thermocouples
Online Contents | 1994
Oxidation Protection for Thermocouples
NTRS | 1984
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