Plasma assisted absorption and reversible desorption of hydrogen gas in zirconium powder using electric discharge assisted mechanical milling method

•Novel method of plasma assisted mechanical milling solid-state hydrogen synthesis.•Both hydrogen absorption and desorption are possible with the single method.•Extremely fast hydrogen absorption.•Low pressure and low average temperature of the process.

This paper presents a novel method of reversible absorption and desorption of hydrogen in metallic powder. This method is based on electrical discharges forming hydrogen plasma, which in ionized state reacts rapidly with metals and alloys to form solid state solutions or metal hydride phases. By selection of proper electric discharge condition, absorption or desorption condition can be created.In our research, we have tested this method on Zr metallic powder. Fast synthesis of zirconium hydride, and reversed decomposition of this compound, was tested using Electrical Discharge Assisted Mechanical Milling (EDAMM) technique in hydrogen plasma environment.ZrH1.8 phase was directly synthesized from zirconium powder within 10 min. Subsequently, hydrogen desorption from pre-prepared ZrH1.8 powder was performed in desorption plasma condition at a low pressure of hydrogen gas. After 30 min up to 80% of hydrogen was extracted from ZrH1.8.All phase and structural changes were investigated by X-ray diffraction (XRD), scanning electron microscopy (SEM) and Carbon-Hydrogen-Nitrogen (CHN) combustion micro-analysis.

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