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Thermal Diffusivity

The rate at which a substance reacts to changes in temperature depends on its thermal conductivity, its density and its specific heat capacity. The thermal conductivity determines how quickly the heat spreads in a fabric. The specific heat capacity indicates how much of this heat is stored in the fabric. The density takes into account how much substance per cubic meter is present. These relationships are described by the thermal conductivity. This substance size is equal to the quotient of thermal conductivity and the product of specific heat capacity and density. From this formula, the unit of measure [m²/s] is calculated.

The thermal diffusivity is required for the assessment of heating and cooling processes, temperature changes in living spaces and thermal stresses in components. For example, the indicator is an important criterion in the classification of civil engineering equipment to prevent fire spread.
If a fast temperature compensation in materials is desired, materials with a high thermal conductivity are advantageous. These include metals and graphite. These substances are used for example in temperature measuring instruments and temperature controllers. Non-metals conduct the temperature significantly worse. They are suitable, among other things, for heat storage in regenerators.

For the measurement of the thermal diffusivity, a material sample is placed between two elements with constant, mutually different temperatures and the local and temporal temperature profile in the sample is evaluated. These elements can be found, for example, in the LINSEIS Heat Flow Meter. Precise measurement data for very thin layers is provided by our TF-LFA – LaserFlash for thin films, which works on the basis of laser beams. The Linseis gauges simultaneously determine the thermal conductivity, the thermal diffusivity and the specific heat capacity based on the included software.

Our measuring devices for measuring the thermal diffusivity

LFA 500

LFA-500

LFA 500 – LightFlash Analyzer – The robust workhorse

Temperature range:

  • -100 up to 500°C
  • RT up to 500°C / 1000°C / 1350°C (1450 with boost)
Details

LFA 1000

LFA-1000

LFA 1000 – True LaserFlash Analyzer – The premium device

Temperature range:

  • -125 up to 500°C
  • RT up to 1250°C/ 1600°C/ 2000°C/ 2800°C
Details

TF-LFA

TF-LFA

Thin Film LaserFlash – Time Domain ThermoReflectance (TDTR)- Thermal diffusivity of thin films

Details

THB

Linseis THB

THB – Transient Hot Bridge – Sandwiched Sensor type Thermal Conductivity and Thermal Diffusivity measurements

Service temperature:

  • –150°C up to 200°C
  • -150°C  up to 700°C
Details

TFA

TFA

Unique device for a comprehensive thin film characterization from the nm to the µm scale

Details

LZT Meter

LZT-Meter

LZT-Meter – Perfect tool for thermoelectric applications

Temperature range:

  • -150 up to 500°C
  • RT up to 800
  • RT up to 1100/1500°C
Details

HFM

Linseis HFM

HFM – Heat Flow Meter – The perfect solution for isolating materials

Temperature range:

  • Fixed 0 to 40°C
  • var. 0 to 100°C
  • -20 up to 75°C
  • var. -30 to 90°C
  • var. -20 to 70°C
Details