Measurement of the thermal properties of slate by the laser flash method

Abstract

The thermal diffusivity of slate has been measured on disk samples of 6 mm in diameter and 1 mm in thickness by the laser flash method. The concept of this method is rather simple: a small, uniform and thermally insulated sample initially at a constant temperature receives a short pulse of energy at the front surface and the transient temperature of the back surface is recorded to acquire the thermal diffusivity. The thermal conductivity has been determined by the measured thermal diffusivity, the slate density and determining the specific heat capacity by means of adiabatic calorimetry. The experimental system for thermal diffusivity measurements has been developed using a pulsed Nd:YAG laser, a vacuum chamber as well as the sample holder which have been designed to allow the coupling to a computer in order to register the temperature evolution.The thermal diffusivity of slate has been measured on disk samples of 6 mm in diameter and 1 mm in thickness by the laser flash method. The concept of this method is rather simple: a small, uniform and thermally insulated sample initially at a constant temperature receives a short pulse of energy at the front surface and the transient temperature of the back surface is recorded to acquire the thermal diffusivity. The thermal conductivity has been determined by the measured thermal diffusivity, the slate density and determining the specific heat capacity by means of adiabatic calorimetry. The experimental system for thermal diffusivity measurements has been developed using a pulsed Nd:YAG laser, a vacuum chamber as well as the sample holder which have been designed to allow the coupling to a computer in order to register the temperature evolution.