Pulverization mechanism of hydrogen storage alloys on microscale packing structure

In-situ and transient visualizations of the packing structure of a hydrogen storage alloy bed are carried out using an X-ray computed tomography (CT) system. The packing structure is clearly observed on the microscale using the CT system. When the alloy bed is subjected to hydrogen absorption–desorption cycles, the pulverization progresses from the lower to the upper regions of the bed. After several hydrogen absorption–desorption cycles, the packing structure in the lower region of the bed changes and the microstructural void decreases slightly. Based on these results, we propose a pulverization mechanism of the packed bed in which the friction between particles affects the pulverization process.

► The visualizations on hydrogen storage alloy bed are carried out by computed tomography.
► The packing structure of the hydrogen storage alloy bed is clearly observed.
► Pulverization in the packed bed progresses from the lower to upper regions.
►  A pulverization mechanism in the packed bed is proposed.
► Results suggest that the friction between particles affects the pulverization process.