Application of the transient step-heating technique for the measurement of in-plane thermal diffusivity

A method for the measurement of in-plane thermal diffusivity for thin-strip materials is presented. It is especially suitable for materials having large length-to-thickness ratio, like thin films, composite laminates, and printed circuit boards. A strip sample is heated at one end, either by direct electric heating or indirect thermal radiation heating. The temperature monitored at the opposite end of the strip serves for thermal diffusivity estimation, by means of a parameter estimation method in conjunction with an analytical solution based on Laplace transformation. A discussion of the sensitivity and the errors of the proposed technique is also included. The uncertainty in the measured thermal diffusivity is better than 5%. Preliminary room-temperature measurements of thermal diffusivity of Armco iron and 304 stainless steel are compared with literature data.