Round Robin Study on the Thermal Conductivity/Diffusivity of a Gold Wire with a Diameter of 30 μm Tested via Five Measurement Methods

Since first establishing thermal measurement techniques for micrometer-scale wires, various methods have been devised and improved upon. However, the uncertainty of different measurements on the same sample has not yet been discussed. In this work, a round robin test was performed to compare the thermal conductivity and thermal diffusivity measurement methods for a fine metal wire. The tested material was a pure gold wire, with a diameter of 30 µm. The wire was cut into certain lengths and distributed to four institutions using five different measurement methods: the direct current (DC) self-heating method, the DC heating T-type method, the 3ω method for thermal conductivity, the scanning laser heating alternating current (AC) method, and the spot periodic heating radiation thermometry method for thermal diffusivity. After completing the measurements, the reported thermal conductivity and thermal diffusivity at room temperature, i.e., 317 W·m⁻¹·K⁻¹ and 128×10⁻⁶ m²·s⁻¹, respectively, were adopted as references for comparison with the measurement results. The advantages and disadvantages of each method are described in terms of the effect of electrical and thermal junctions fabricated on a wire, such as an electrode, a thermocouple, and a heat bath. The knowledge obtained from the tested methods will be useful for selecting and designing a measurement technique for various wire-like materials.