Thermal Diffusivity Measurement for Thermal Insulator Composite Material with Silica Nanoparticles/Glass Fiber by the Laser Flash Method

It is required to obtain quickly thermal conductivities of small specimens by simple measurement techniques to promote material development. Thermal conductivity measurement for thermal insulators usually needs long time, for example, a few days by the guarded hot plate method using a large specimen. It is useful for material development if more quick measurement of thermal conductivity is done with small specimens. The flash method is one of the promising methods to get thermal diffusivity in short time without contacts. However, only thermal diffusivity of dense solid has been measured by the flash method. In this study, laser flash method was applied to measure the thermal diffusivity of thermal insulators which consist of silica nanoparticles and glass fiber. As a result, it was made clear that the laser flash method was reliable for the measurement of thermal insulators. Besides, it was found that the thermal diffusivity of the thermal insulators was influenced by the content ratio of hydrophilic and hydrophobic silica nanoparticles.