Transient calorimetric technique for measuring total hemispherical emissivities of metals with rigorous evaluation of heat loss through thermocouple leads

An apparatus for the transient calorimetric technique used for measuring the total hemispherical emissivities of metals has been developed. Measurements have been made on specimens of copper and aluminum in the temperature range of 330–630 K. An exact analysis is given of the conduction heat loss through thermocouple leads suspending the specimen. From the numerical results of the lead-wire heat loss, the significant effect of a guard heater employed in the apparatus is illustrated. By taking account of the heat loss, the emissivities of the specimens are accurately evaluated and are compared with the data of previous investigators.