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Laser Flash Method Measurement Principles for thermal measurement device LFA-502

LFA-502 laser flash thermal measurement device

In just a few seconds of heating the sample, the coefficient of thermal diffusivity/specific heat can be found. The thermal conductivity rate is then calculated. This measurement device is becoming more common, but has become much more accurate than previous devices with the coefficient of thermal diffusivity rate measurement technology of recent years.

Specific heat can be precisely measured at the same time, and that function relied upon the DSC (differential scanning calorimeter) previously. Thin materials with a high thermal conductivity rate (copper, aluminum, aluminum nitride) can also be measured precisely.

Laser Flash Method:Measurement Principles for thermal measurement device LFA-502

In the laser flash method, a laser pulse of 1ms width or less is used to momentarily heat the front side of a 5-10 mm diameter, 2mm thick discoid sample, and the back side temperature change is measured.

According to the theoretical solution proposed for insulation conditions, the sample backside temperature increases, and the temperature rise becomes a constant value (ΔT) after uniform temperature distribution is achieved. In previous analysis, the time t1/2 until the coefficient of thermal diffusivity α attained ΔT/2 results from α=0.1388d2/t1/2 (d is the thickness of sample). (t1/2 method)


From the coefficient of thermal diffusivity α found by laser flash method, and the specific heat volume found by another method and the density ρ, we calculate the thermal conductivity rate λ by λ=αcρ.