Cold Gas-Dynamic Spray for Catalyzation of Plastically Deformed Mg-Strips with Ni Powder

Abstract

Magnesium hydride (MgH2) has received significant attention due to its potential applications as solid-state hydrogen storage media for useful fuel cell applications. Even though MgH2 possesses several attractive hydrogen storage properties, it cannot be utilized in fuel cell applications due to its high thermal stability and poor hydrogen uptake/release kinetics. High-energy ball milling, and mechanically-induced cold-rolling processes are the most common techniques to introduce severe plastic deformation and lattice imperfection in the Mg/MgH2. Furthermore, using one or more catalytic agents is considered a practical solution to improve both the de-/rehydrogenation process of MgH2.These treatments are usually dedicated to enhance its hydrogen storage properties and deduce its thermal stability. However, catalyzation of Mg/MgH2 powders with a desired catalytic agent using ball milling process has shown some disadvantages due to the uncontrolled distribution of the agent particles in the MgH2 powder matrix. The present study has been undertaken to employ a cold gas-dynamic spray process for catalyzing the fresh surfaces of mechanically-induced cold-rolled Mg ribbons with Ni powder particles. The starting Mg-rods were firstly heat treated and forged 200 times before cold rolling for 300 passes. The as-treated ribbons were then catalyzed by Ni particles, using cold gas-dynamic spray process. In this catalyzation approach, the Ni particles were carried by a stream of Ar gas via a high-velocity jet at a supersonic velocity. Accordingly, the pelted Ni particles penetrated the Mg-substrate ribbons, and hence created numerous micropores into the Mg, allowed the Ni particles to form a homogeneous network of catalytic active sites in Mg substrate. As the number of coating time increased to three times, the Ni concentration increased (5.28 wt.%), and this led to significant enhancement of the Mg-hydrogen storage capacity, as well as improving the de-/rehydrogenation kinetics. This is evidenced by the high value of hydrogen storage capacity (6.1 wt.% hydrogen) and the fast gas uptake kinetics (5.1 min) under moderate pressure (10 bar) and temperature (200 °C). The fabricated nanocomposite MgH2/5.28 wt.% Ni strips have shown good dehydrogenation behavior, indicated by their capability to desorb 6.1 wt.% of hydrogen gas within 11 min at 200 °C under 200 mbar of hydrogen pressure. Moreover, this system possessed long cycle-life-time, which extended to 350 h with a minimal degradation in the storage and kinetics behavior.

Synthesis, and characterization of metallic glassy Cu–Zr–Ni powders decorated with big cube Zr2Ni nanoparticles for potential antibiofilm coating applications

“…This was the primary factor in the selection of this method. The cold spray process is taking place by utilizing high-velocity particles, which, upon impact with a substrate or previously deposited particles, convert the particle's kinetic energy into plastic deformation, strain, and heat 42 .

Figure 11 An onsite photo displays the cold spray coating procedure used to prepared MG coated/ SUS 304 at 550 °C for five continuous times.

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“…It has been pointed out that 90% of the applied impact energy on the particle/substrate materials is converted into local heat 40 . Additionally, when the impact stresses are applied, high plastic strain rates are achieved in the contact particle/substrate zone within a very short time 41 , 42 .…”

“…It provides a means of overcoming significant constraints of conventional thermal spray technologies, in which the powders must be melt during the thermal spray technique in order to be deposited onto the substrate. Obviously, this traditional coating process is not suitable with the materials that are very sensitive to temperature, such as nanocrystalline, nanoparticles, amorphous, and metallic glasses 40 – 42 . Moreover, the as- thermal spray coating material are always show high levels of porosity and oxide.…”

Research on Energy and Economics of Self-Made Catalyst-Coated Membrane for Fuel Cell under Different Oxidants

“…However, due to the problems of high initial investment and low energy density, it is necessary to continue to study this technology to improve its commercial application value. At present, the research on PEMFC mainly focuses on performance improvement, power system design and materials economics [3][4][5][6][7][8], and less on oxidants.…”

Effect of ZrC Nanopowders on Enhancing the Hydro/Dehydrogenation Kinetics of MgH2 Powders

“…Within the last decade, some advanced nanocarbon materials, such as single-walled carbon nanotubes [ 43 ] and graphene nanofibers [ 44 ], have shown remarkable beneficial effects on changing the hydrogen storage properties of Mg/MgH 2 . In 2021, a novel catalyzation process was proposed to enhance the thermodynamics and kinetics behaviors of Mg metal using Ni powders via a cold spray process technique [ 45 ].…”