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

Abstract

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Reconstruction and modeling of 3D percolation networks of carbon fillers in a polymer matrix

“…Such an evidence suggests an indirect method for computing the global thermal conductivity corresponding to phases with large conductivity ratios (e.g., k f /k p > 100), where it becomes desirable to avoid both significant numerical errors (u g < 0.2) and long computations (u g z 2). Moreover, the anisotropy of the k eff in such a composite material is demonstrated by computing the ellipse of thermal conductivity, consistently also with experimental evidences [23]. Finally, it is worth stressing that the numerical tool described in this work may be utilized, in combination with experimental data, for characterizing the contact between filler particles in a percolating path.…”

“…7 for different values of q, and a typical ellipse of thermal conductivity of highly anisotropic materials is shown. Notice that, anisotropy of thermal conductivity typically arises from experiments on composite materials, and the ellipse of thermal conductivity can be observed by using, for instance, photoreflectance microscopy (see, e.g., [23]). Each configuration S i¼1, ., 10 reported in Table 2 and in Fig.…”

Microscopic thermal diffusivity measurements of ceramic and metallic foams lumps in temperature

“…2). A thermal enclosure enables the experiment to be conducted under vacuum controlled atmosphere conditions up to 1000 C [26], and an autofocusing system ensures the pump beam focus accuracy and the long-term measurement stability. A computer connected to all the measuring instruments controls data acquisition and storage.…”

New Apparatus for Thermal Diffusivity and Specific Heat Measurements at Very High Temperature

“…Until now, efforts have been made for the measurement of thermal diffusivity at microscopic scale at temperatures up to 1300 K [1]. But, at macroscopic scale, thermal diffusivity and specific heat measurements were only performed at temperatures up to 800 and 1000 K, respectively.…”