3.1 Thermal diffusivity is an important property required for such purposes as design applications under transient heat flow conditions, determination of safe operating temperature, process control, and quality assurance.

3.2 The flash method is used to measure values of thermal diffusivity (α) of a wide range of solid materials. It is particularly advantageous because of the simple specimen geometry, small specimen size requirements, rapidity of measurement, and ease of handling materials having a wide range of thermal diffusivity values over a large temperature range with a single apparatus. The short measurement times involved reduce the chances of contamination and change of specimen properties due to exposure to high temperature environments.

3.3 Thermal diffusivity results in many cases can be combined with values for specific heat (C_p) and density (ρ) and used to derive thermal conductivity (λ) from the relation λ = αC_pρ.

This test method can be used to characterize graphite for design purposes.

1.1 This test method covers the determination of the thermal diffusivity of carbons and graphite to ±5 % at temperatures up to 500°C. It requires only a small easily fabricated specimen. Thermal diffusivity values in the range from 0.04 to 2.0 cm²/s are readily measurable by this test method; however, for the reason outlined in Section 5, for materials outside this range this test method may require modification.

1.2 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.