Effects of short-term mechanical milling and catalyst on the hydrogen storage performance of ZK60 alloy modified by mischmetal and severe plastic deformation

Abstract

In this study, the ZK60Mm alloy (Mm = Ce-based mischmetal) was processed by equal channel angular pressing (ECAP), friction stir processing (FSP), and high-strain rate rolling (HSR), followed by short-term mechanical milling with graphene and palladium. All of the samples processed by severe plastic deformation (SPD) process, followed by short-term ball milling, could absorb ∼6 wt% of hydrogen within 5 min at 300 °C. Results indicate that the addition of Mm, catalyst (graphene and palladium), and short-term ball milling improved hydrogen storage kinetics and capacity. In contrast, the SPD method was less critical for enhancing kinetics and capacity. The FSP-treated sample maintained a capacity of approximately 5 wt% after 200 hydrogenation cycles, showing a reduction of 19 %. The findings highlight the critical role of processing techniques and additives in optimizing the hydrogen storage properties of the ZK60 alloy.