Micron-scale thermal characterizations of interfaces parallel or perpendicular to the surface

Abstract

Theoretical and experimental possibilities are presented of a modulated photothermal method, laser-induced photoreflectance, for inspecting thermal diffusivities and quality of interfaces in composite materials with micron-scale spatial resolutions. The models are established for semi-infinite materials containing interfaces parallel or perpendicular to the sample surface. The applications concern thermal diffusivity measurements of anisotropic polycrystals and detection of thermal resistance in damaged materials and at interfaces between reinforcements and matrix in composites.

Photothermal mirage characterization of vertical interfaces separating two different media

“…7,8 As a particular case, Lepoutre et al 8 modeled the surface temperature produced by a vertical interface separating two different media. This problem is of interest for example for the thermal characterization of the junction between two solids ͑e.g., weldings͒ or in the control of the quality of contacts between different parts of composite materials that governs, for example, the lifetime of the system.…”

Open photoacoustic cell determination of the thermal interface resistance in two layer systems

“…1,5 In particular photothermal techniques have been shown to be very reliable and efficient tools for thermal characterization of multilayered systems. [6][7][8][9][10][11][12] The effects of thermal resistance in the photothermal signal, 10,11 coatings, 13 buried layers, 14 air gaps, 15 damage, 9 inspection of boundaries, 12 among many others have been considered.…”

Thermal properties measurements of a silica/pyrocarbon composite at the microscale

“…In order to simulate the probe temperature when the probe sweeps the surface of the composite at a given frequency, we used the analytical model derived by Lepoutre et al 26 assuming semi-infinite domains on both sides of the interface. This assumption is realistic since the probe is only sensitive to the material bulk thermal conductivity at distances that do not exceed 5 to 6 times the contact radius r 0 .…”