Characterization of thermal transport and laser absorption properties of an individual graphitized carbon fiber by applying Raman thermography

Graphitized carbon fibers have potential applications owing to their excellent electrical, mechanical, thermal and optical properties. Thermal transport and laser absorption properties are the fundamental parameters for the thermal design, but difficult for determining due to their very small characteristic sizes. In this study, we systematically investigated the temperature (T)-dependent apparent thermal conductivity (λa), thermal conductivity (λ), thermal contact resistance (Rc, between sample and heat sink) and laser absorptivity (α) of an individual graphitized carbon fiber using a non-contact Raman method. This method and the experimental system were verified by comparing the measured thermal conductivity of a 10.0 μm diameter platinum wire with the standard data. The measured λ of this graphitized carbon fiber decreases from 372.4 to 330.1 W/(m·K) as T increases from 338 to 496 K, indicating the three-phonon Umklapp scattering rate increases with temperature. Rc increases with T from 3.44 × 103 to 6.35 × 103 K/W in this experimental temperature range, and the laser (488 nm wavelength) absorptivity is determined to be 0.90 ± 0.02.