The following LFA measurements show the investigation of copper using two methods: the through-plane and in-plane measurement method.
For the through-plane measurement method a sample of 1.43 mm thickness and a “standard” sample holder was used. For the in-plane measurement a 40 µm thin copper foil in the in-plane adapter was measured.
The measurement was performed at room temperature 10 and 15 times, respectively. The wait time between two measurements was set to two minutes to ensure that the sample has cooled down completely.
The average value for the through-plane measurement is 1.16 cm²/s and the standard deviation shows the high repeatability accuracy of the LFA measurement. The average obtained by the in-plane measurement is approximately 1.20 cm²/s.
The literature value for the thermal diffusivity of copper is 1.17 cm²/s. Thus, with the through plane measurement a deviation of only 0.85 % and with the in-plane method a deviation of about 2 % are achieved and show the high measurement accuracy of the LFA device.
