Laser Flash Analysis / LFA 457 MicroFlash

A Laser-Flash-Apparatus (LFA) is able to measure the thermal diffusivity D of a sample in a wide temperature range without time-consuming sample preparation steps. The technique uses a short laser pulse, which is absorbed at the front surface of the sample. The temperature of the rear surface of the sample is recorded as a function of time. From the evolution of the temperature signal, the thermal diffusivity D can be determined. Furthermore, by measuring a standard sample simultaneously, the specific heat Cp can be obtained, which is crucial for the determination of the thermal conductivity κ=ρDCp, where ρ is the sample density.

Our laboratory offers a LFA 457 MicroFlash (NETZSCH-Gerätebau GmbH). High and a low temperature furnaces are available to cover the temperature range between -100°C and 1100 °C. An automatic sample change allows measurements of three samples at the same time. The software includes various models to determine the diffusivity D. Further, the specific heat can be determined if a standard sample is measured simultaneously. Standard samples are available for the sample holders with a diameter of 6, 8, 10, and 12.7 mm. The software also calculates the thermal conductivity κ if the sample density ρ and the specific heat Cp are known.

Fig. 1:  LFA 457 MicroFlash

Fig. 1: LFA 457 MicroFlash

Temperature range -100 °C…500 °C (low temperature furnace); room temperature…1100 °C (high temperature furnace)
Geometry of quadratic samples 6 x 6 mm2, 8 x 8 mm2
Geometry of circular samples Ø6, Ø8, Ø10, Ø12.7 mm
Thickness of the samples 0.1 mm…6 mm depending on thermal conductivity
Gas atmospheres He, N2, Ar
Measurement range D 0.01 mm2/s … 1000 mm2/s
Measurement range κ 0.1 W/(m*K)…2000 W/(m*K)
Accuracy of D ±3%
Accuracy of Cp ±5%
Repeatability of D ±2%
Repeatability of Cp ±3%