Corrections for nonuniform surface-heating errors in flash-method thermal-diffusivity measurements

Abstract

The effects of nonuniform surface heating in the flash method of thermal-diffusivity measurement are investigated theoretically and experimentally. An expression for the temperature response with nonuniform surface heating is presented. Evaluation of this expression shows that 30% nonuniformity results in diffusivity errors of 0.1–7.4%, depending on the method of data reduction used. It is shown experimentally that corrections for nonuniform heating can be made with this expression given quantitative information about the nonuniformity, in this case reducing the error from 26% to zero.