Laser Flash Apparatus (LFA)
To measure thermal diffusivity and thermal conductivity in a wide range our laboratory is equipped with a MicroFlash 457 laser flash apparatus from NETZSCH Gerätebau GmbH (Germany).
The instrument allows measurements from -125°C to 1100°C. The instrument can be used for small and large sample sizes of up to 25.4 mm diameter and, with the integrated sample changer, measurements can be run on several samples at the same time. In addition to the regular sample holders, custom ones are available on request. To reduce nonuniform heating, an optical homogenizer is additionally placed beneath the sample and to minimize disturbing sideways radiation to the detector a thin iron plate lining is emplaced between the sample and the detector. The data evaluation can be performed using the integrated software system by NETZSCH or by custom-built software suite based on python programming language. They all include pulse-time corrections, heat loss considerations, thermal extension corrections, and more.
Key Technical Data
- Temperature range: -125 °C to 1100 °C
- Thermal diffusivity range: 0.01 mm²/s to 1000 mm²/s
- Detector types: MCT (HgCdTe) and InSb
- Time resolution: 4 µs
- Heating/cooling rate: 0.01 K/min to 50 K/min
- Laser energy: max. 18.5 J/pulse, adjustable
- Sample dimensions: cylindric (3 mm, 0.5” and 1.0” diameter), squared (10 mm), custom-built
- Liquid sample holders: sapphire (metals) and aluminium/platinum
S. Breuer, F.R. Schilling, Improving Thermal Diffusivity Measurements by Including Detector Inherent Delayed Response in Laser Flash Method, Int. J. Thermophys. 40(10), 95-111, doi:10.1007/s10765-019-2562-9
J. Blumm, A. Lindemann and B. Niedrig, Measurement of the thermophysical properties of an NPL thermal conductivity standard Inconel 600, High Temp. - High Press. 35/36 (2003/2007), doi:10.1068/htjr145
I.M. Abdulagatov, Z.Z. Abdulagatova, S.N. Kallaev, A.G. Bakmaev and P.G. Ranjith, Thermal-Diffusivity and Heat-Capacity Measurements of Sandstone at High Temperatures Using Laser Flash and DSC Methods, Int. J. Thermophys. 36, (2015), doi:10.1007/s10765-014-1829-4
Rhodolite garnet single crystal thermal diffusivity. Custom sample holder for sample diameter: 3.1 mm and sample thickness: 0.322 mm. Data fit after Roufosse & Klemens (J. Geophys. Res. 79, 1974)