Hot-rod thermography for in-plane thermal diffusivity measurement

Active thermography is one of the techniques used for thermal diffusivity measurement by inducing a thermal contrast in the specimen, typically a laser based approach. In this work, we present a simple heat source in the form of a heated rod and the subsequent technique is named as Hot-Rod thermography. This simple source is more cost effective and can be implemented with minimal precautionary measures. The proposed source is a modified soldering rod which is heated to a particular temperature and kept in contact with the sample for a fixed duration so that heat will be transferred through the material and the resulting temperature diffusion pattern is observed at the rear side of the sample via Infrared camera. The movement of the hot-rod may be automated. This hot-rod thermography is demonstrated through thermal diffusivity measurement on a stainless steel specimen and the obtained results are validated using Modified Transient Plane Source technique.