Thermal conductivity and thermal diffusivity are the most important thermophysical material parameters for the description of the heat transport properties of a material. Common techniques for determining Thermal ConductivityThermal conductivity (λ with the unit W/(m•K)) describes the transport of energy – in the form of heat – through a body of mass as the result of a temperature gradient (see fig. 1). According to the second law of thermodynamics, heat always flows in the direction of the lower temperature.thermal conductivity include the Heat Flow Meter (HFM) and Guarded Hot Plate (GHP). For the precise measurement of thermophysical properties such as Thermal DiffusivityThermal diffusivity (a with the unit mm2/s) is a material-specific property for characterizing unsteady heat conduction. This value describes how quickly a material reacts to a change in temperature.thermal diffusivity, the Laser Flash technique (LFA) has proven itself as a fast and precise method.
In Laser Flash Analysis, a short energy light pulse heats the front surface of a plane-parallel sample. From the resulting temperature increase of the rear face measured with an infrared (IR) detector, the Thermal DiffusivityThermal diffusivity (a with the unit mm2/s) is a material-specific property for characterizing unsteady heat conduction. This value describes how quickly a material reacts to a change in temperature.thermal diffusivity and, if a reference specimen is used, specific heat can both be determined.
Not only sample preparation plays an important role for LFA measurements, but also other essential things have to be taken into account. Learn in our new video about the basic workflow of an LFA measurement:
- Preparing the detector
- What to consider when preparing the sample and why a graphite coating is necessary
- The difference between high- and low-temperature systems
- Which sample holder to choose depending on your sample
- How to define the temperature program
- Evaluation methods for your measurement using the PROTEUS®Software
Watch the video here:
For more information about laser flash analysis, please visit our website.
These LFA articles might also find your interest:
LFA Measurements with Graphite Coating: Tips and Tricks (ta-NETZSCH.com)
Thermal Management of Heat Transfer Materials (TIMs) (ta-NETZSCH.com)
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