Decrepitation process of hydride forming material observed by Neutron Radiography

BIASETTI, A.T.; MARÍN J.; BARUJ A.; MEYER, G.O.; BORZONE, E.M.

Buenos Aires

Congreso; ITMNR-9 - 9th International Topical Meeting on Neutron Radiography; 2022

Hydride-forming materials are widely investigated for hydrogen storage,separation and purification, due to its reversible reaction with hydrogen at moderatedpressures, and to its high volumetric hydrogen capacity. Among the technicalconstraints for practical applications is the improvement of the operatingconditions of a potential hydrogen reservoir within the framework of these HydrogenTechnologies. Specifically, regarding the mechanical properties of thesematerials mainly used in powder form, the considerable change in cell volumeduring the reactions with hydrogen (21% for the used LaNi5) isresponsible for exerting significant mechanical stresses upon the vessel walls.  Our group has been studying this phenomenon by measuring the correspondingmechanical strains generated on the wall during hydrogen absorption/desorption cycling.However, the complexity of studying this mechanical effect arises from the factthat the granulometry, porosity and flowability of the powder material areaffected themselves by the processes of decrepitation along the cycles. In thatway, neutron imaging has proven to be an efficient technique to visualize theevolution of the powder rearrangement inside the reservoir. By means of thistechnique, we have identified some key aspects for understanding therelationship between the degree of compactation of the powder, the geometricalparameters of the reservoir (slenderness, wall thickness, filling level), theequivalent pressure exerted by the material against the reactor walls, as wellas the number of cycles.We present here the results obtained in the RA6 neutronimaging facility to continue the previous reported work.