A Steady-State Thermal Gradient Generator for Material Characterization Using an Induction Heating System

Mobility/diffusion of ions can occur mainly in two situations. The first one when a potential difference is applied to electrodes of an electrochemical device as in batteries for instance (i.e., charge/discharge). In the second one, the diffusion process is driven by the thermal gradient existing within the material. This article deals with the design of a controlled thermal gradient generator (TGG), which opens the way to thoroughly study the effect of temperature difference on the chemical diffusion and mechanical resistance of shaped samples (e.g., a pellet and a rod). This TGG uses a combination of two susceptors involving the control of their respective temperatures. One is controlled by adjusting the power of a high-frequency generator that supplies an induction heating coil. The other is controlled, mainly, by the displacement of the sample/susceptors set through this same coil, with a motorized stage. The operation and control parameters are defined within a dedicated user-friendly software application. During the whole experiment, the two temperatures can be varied, while the inner thermal gradient of the sample is kept constant, as long as these temperatures are high enough.