Carbon fiber polymer-matrix composite interfaces as thermocouple junctions

Thermocouples made from dissimilar continuous carbon fibers in the form of epoxy-matrix composite, using the interlaminar interface as the thermocouple junction, were found to exhibit thermocouple sensitivity that is close to the difference between the Seebeck coefficients of the two partners of the thermocouple. The highest thermocouple sensitivity of 82 uV/°C was obtained by using Thornel P-100 carbon fibers that had been intercalated with bromine and sodium. The thermocouple sensitivity was the same for unidirectional and crossply junctions. Two crossply laminae comprising dissimilar carbon fibers provided an array of junctions, each of which was a thermocouple, thus allowing temperature distribution sensing.