The latest version of our LFA Proteus®® software provides a quick and accurate way to determine in-plane 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, even for highly orthotropic materials.
Our specially developed model for orthotropic materials enables accurate analysis of heat transport within the plane, taking into account the material’s directional properties.
The Challenge: Direction-Dependent Heat Conduction
In the electronics industry, materials for heat dissipation are highly sought after. Graphite foils are often used for this purpose, but other materials that exhibit orthotropic behavior are also used. This means their thermal properties vary depending on the direction. Typically, in-plane 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 is much higher than through-plane diffusivity, which allows for rapid heat dissipation to the sides.
LFA software packages typically employ a one-dimensional evaluation model for in-plane measurements that only considers in-plane diffusivity and disregards the impact of through-plane heat flow. However, to correctly evaluate in-plane measurements, it is crucial to consider the influence of through-plane conductivity. Neglecting this can lead to significant deviations, particularly when the through-plane and in-plane properties differ greatly.
Our Solution
Our mathematical model, the in-plane orthotropic model, evaluates in-plane diffusivity by accounting for known through-plane diffusivity.
Precondition: The through-plane diffusivity must be determined beforehand (e.g., via a standard LFA through-plane measurement).
Then, the model fits the measured temperature curve from the in-plane experiment to provide a highly accurate in-plane diffusivity result.
The model correctly represents heat flow in all directions, ensuring physically meaningful and reproducible results, even for strongly anisotropic materials.