Exothermic Phenomena in Hydrogen Desorption Experiments Using Pd-Ni Samples

In this study, we conducted a hydrogen desorption experiment using a Pd foil sample coated with a Ni membrane to investigate its thermal behavior and hydrogen diffusion characteristics. Two heating methods were employed: direct heating and indirect heating. In the direct heating experiments, transient heat generation was observed 0.5–1.0 hours after applying constant power, accompanied by temperature changes associated with hydrogen release. Comparison with unabsorbed samples suggested that the excess heat was estimated to be up to several hundred milliwatts. On the other hand, in the indirect heating experiments, heat generation was rarely observed, but a heat generation phenomenon was confirmed when a constant power of 1 W was applied. These results suggest that anomalous diffusion during the hydrogen desorption process may induce heat generation, indicating the need for further confirmation of reproducibility and higher-precision evaluation of excess heat.