A high-precision method to measure thermal conductivity of solids using reversible heat flux

In the thermal conductivity measurement of solids using the traditional steady-state methods, it is observed that the test results differ from their standard values when only one directional heat flux is introduced. Analysis of the results shows that the additive errors are considerable and cannot be ignored. To minimize the additive errors, a high-precision method by alternating the direction of heat flux in steady-state thermal conductivity measurement of solids is proposed. In this method, the additive errors are diminished by using the data corresponding to both forward and reverse heat flux. Meanwhile, a modified thermal instrument is designed and established to measure the thermal conductivity of solids. Simultaneous calibration of the thermal instrument has been processed to improve the measurement accuracy of temperature readings. The thermal conductivities of samples 99.999% standard pure copper and Elkonite copper–tungsten alloy 30W3 are measured and compared with their reference values to verify the accuracy of the method. The results indicate that the processing data well match the reference values. (paper)