THERMAL CONDUCTIVITY MEASUREMENTS OF REDUCED-SIZED HIGH-CONDUCTING SHEETS WITH THE HOT DISK THERMAL CONSTANTS ANALYSER

摘要

In the industry today, there is interest to develop high-conducting sheets with a thermal conductivity that exceeds 1700 W/mK. When utilizing the Hot Disk Thermal Constants Analyser for testing a 20-100-micron thick sheet, around 1700 W/mK, a double-sided setup is required, with 80 mm × 80 mm or larger sheet. The in-plane thermal depth of probing, computed from the duration of heating and the thermal diffusivity, needs to be less than 38 mm if using a Hot Disk sensor of diameter 4 mm. In the following, it is investigated if in-plane down-scaling of the Hot Disk sample setup is possible, by positioning of a Hot Disk sensor in a corner of a "mirrored" sample setup. It is assumed that the temperature- νｓ. time response for this mirrored setup will be similar to that of the twice as large Hot Disk sensor placed in the centre of a tested sheet four times as large. Preliminary results indicate that for high- conducting samples, above 100 W/mK, the geometrical deviations within the near-sensor zone of the mirrored setup can be neglected by omitting some additional data points in the beginning of the transient curve. It appears that for tests on Aluminium, a mirrored setup will yield valid and accurate thermophysical data, fully comparable to results obtained in a regular Hot Disk setup.