Hydrogen Production Properties of Aluminum–Magnesium Alloy Presenting β-Phase Al₃Mg₂

In this study, aluminum–magnesium (Al-Mg) bulk porous materials were fabricated by using uniaxial hot pressing to control the porosity rate of the material over a wide range (up to 50%). The fabricated materials were analyzed by X-ray diffraction and scanning electron microscopy. The results demonstrated the appearance of intermetallic (IM) phase Al3Mg2, and its quantity increased with the applied pressure. In the context of the decline of global fossil fuel reserves, the revalorization of these materials by hydrogen (H2) production was investigated. Hydrolysis of the Al-Mg materials was carried out in a simulated seawater solution (aqueous solution of sodium chloride 35 g/L). The results showed the role of the porosity rate in the H2 production properties of the fabricated materials; the increase of porosity rate from 10% to 50% cuts the reaction time in half. Finally, the role of IM phase Al3Mg2 in H2 production was highlighted through galvanic coupling

Hydrogen Generation from Mg Wastes by Cold Rolling and Ball Milling by Hydrolysis Reaction: Elektron 21 (UNS-M12310) in Simulated Seawater

Hydrolysis is an efficient way of producing hydrogen by using Mg-based waste. In this study, H2 production is realized in simulated seawater (i.e., 3.5 wt.% NaCl) using the Elektron21 (EL21) alloy as a reagent. This alloy is a magnesium-based alloy composed of 96 wt.% Mg and 4 wt.% rare earth (approx. 3 wt.% Nd and 1 wt.% Gd). EL21 is known for its excellent corrosion resistance and high tensile strength. The impact of different mechanical treatments (ball milling, cold rolling, cryo rolling, and cryo ball milling) on the hydrolysis yield of the material was discussed. A pretreatment with cryo rolling before ball-milling treatment shows the best hydrolysis performance, with a yield of 90.5% achieved in 10 min in salted water. The ductile-to-brittle transition induced a modification of the microstructure, which explains the good hydrolysis performances

Study on debinding and sintering conditions in extrusion-based additive manufacturing of 316L and 316L + Cu

International audienceThis study investigates the use of a methylcellulose binder in extrusion additive manufacturing of 316L as an alternative to common wax-based binders. Various quantities of copper (Cu) powder were also added in the paste composition to attempt to reduce the sintering temperature by promoting persistent liquid phase sintering. Debinding experiments were conducted under different temperatures and dwell times using argon (Ar), Ar/5%H 2 , and Ar/1%O 2 atmospheres. Debinding reduced carbon (C) content to 0.032 wt.% by using a two-step debinding process of Ar/5%H 2 and Ar/1%O 2 thermal treatments. Using this debinding process, sintering was conducted at 1200 • C under Ar/5%H 2 atmosphere with the presence of 0, 10, and 20 vol.% Cu in the paste. Microstructure, mechanical, and corrosion properties were studied. Cu additions allowed the improvement of the densification when sintering at 1200 • C was performed. A 20 vol.% Cu addition yielded 88% relative density after sintering for 10 h, while pure 316L powder sintered under the same conditions had 70%. Mechanical properties were inferior to fully dense stainless steel, but it is not clear if this is due to the Cu additions or insufficient densification

Study on Debinding and Sintering Conditions in Extrusion-Based Additive Manufacturing of 316L and 316L + Cu

This study investigates the use of a methylcellulose binder in extrusion additive manufacturing of 316L as an alternative to common wax-based binders. Various quantities of copper (Cu) powder were also added in the paste composition to attempt to reduce the sintering temperature by promoting persistent liquid phase sintering. Debinding experiments were conducted under different temperatures and dwell times using argon (Ar), Ar/5%H2, and Ar/1%O2 atmospheres. Debinding reduced carbon (C) content to 0.032 wt.% by using a two-step debinding process of Ar/5%H2 and Ar/1%O2 thermal treatments. Using this debinding process, sintering was conducted at 1200 oC under Ar/5%H2 atmosphere with the presence of 0, 10, and 20 vol.% Cu in the paste. Microstructure, mechanical, and corrosion properties were studied. Cu additions allowed the improvement of the densification when sintering at 1200 oC was performed. A 20 vol.% Cu addition yielded 88% relative density after sintering for 10 h, while pure 316L powder sintered under the same conditions had 70%. Mechanical properties were inferior to fully dense stainless steel, but it is not clear if this is due to the Cu additions or insufficient densification