Microscopic Thermal Characterization of C/C Composites

Assessment of geometrical and transport properties of a fibrous C/C composite preform as digitized by x-ray computerized microtomography: Part II. Heat and gas transport properties

“…In lack of precise measurements, we will refer to studies conducted by Sauder [46], who deduced from electrical resistivity measurements the longitudinal conductivity of carbon fibres. According to Jumel et al [47], the thermal conductivity of carbon fibres lies between 4 and 10.5 W.m -1 .K -1 . A value of 5 W.m -1 .K -1 has been retained for this study.…”

“…A value of 5 W.m -1 .K -1 has been retained for this study. The values determined by Jumel et al [47,48] for the pyrocarbon deposit have been used.…”

Microscale thermal characterization at temperatures up to 1000°C by photoreflectance microscopy. Application to the characterization of carbon fibres

“…As in the case of isotropic materials, the actual energy distributions of the pump and probe beams can be taken into account to calculate the exact periodic temperature increase at the surface of a thermally anisotropic sample [11]. But practically, because of the number of parameters we need to adjust, we use the basic description of the periodic temperature elevation (equations ( 5) and ( 6)) to analyse the photoreflectance measurements that we perform on anisotropic materials [7].…”

“…Until now, C/C composites were characterized with this technique only at room temperature [7] whereas thermal diffusivity measurements at various temperatures have already been performed by infrared microscopy with a 30 µm spatial resolution [8]. Our purpose is to measure the thermal diffusivities of the constituents of C/C composites heated at temperatures up to 1000˚C.…”

Measurement of the thermal diffusivity of a silica fiber bundle using a laser and an IR camera

“…Many methods exist for carbon fibers, which are based on their electrical conductivity [1] ; not all of them are applicable to insulating materials such as glass or silica fibers. Photothermal microscopy [2] has been investigated on C/C composites [3] and in-situ characterization of a carbon fiber thermal diffusivity was made. Photoacoustics [4] and thermal flash under microscope [5] have been used for the measurement of glass fiber heat diffusivity.…”