Storage alloys compositions

M. Zhu, Y. Gao, X.Z. Che, Y.Q. Yang, C.Y. Chung, Hydriding kinetics of nano-phase composite hydrogen storage alloys prepared by mechanical alloying of Mg and MmNi (CoAlMn), J. Alloys Compd. 330-332 (2002) 708-713. 

Y. Kojima, Y. Kawai, T. Haga, Magnesium-based nano-composite materials for hydrogen storage, . /. Alloys Compd. 424 (2006) 294-298. 

The R(Ni,Fe,Al)5 hydrogen storage alloy prepared on the base of the commercial cerium ligature (R = Ce, La, Pr, Nd), lanthanum and nickel (both of technical purity grade) has been used in the unit. The composition of the alloy must provide a hydrogen equilibrium pressure of 10 bar over MH at room temperature and above 150 bar at elevated temperatures. 

The physical and chemical nature of the metal substrate surface depends on the bulk alloy composition, processing conditions used, and any preconditioning environments that the substrate may be exposed to during fabrication and storage. Once the joint is assembled, the physical and chemical nature of the adhesive-metal interface may change due to the environment and to the chemical nature of the adhesive. 

Furthermore, to realize certain hydrogen release pressures the storage tank needs to be kept at a certain temperature level which again depends on the exact alloy/ composite composition. Therefore, there is a lower limit for the temperature of the generated heat so that it can be used directly without any additional heat pumps so on, for heat supply to the storage tank. This shows that the reaction enthalpy is a... 

Some criteria for the design of hydrogen storage alloys will be discussed in this section. For the design of new alloys, it is important first to select the constituent elements and then to determine the alloy composition. 

The catalytic activity of CaNis hydrogen storage alloy is studied for decomposition of diethyl ether in the temperature range between 570 and 720 K by an atmospheric flow method. The alloy showed a catalytic activity at temperatures higher than 570 K. Following mechanism is proposed on the basis of the effect of W/F on the composition of products. Ethane and acetaldehyde are the initial products, while methane and carbon monoxide are the secondary products, formed by the decomposition of the acetaldehyde. 

Fig. 6. Pressure-composition isotherms of the hydrogen storage alloy H system (Schlap-bach 1988).

The lanthanides can form hydrides (qv) of any composition up to LnH. Lanthanide hydrides can desorb hydrogen reversibly with temperature. Therefore, the lanthanides and some of thek alloys ate good candidates for hydrogen (qv) storage, of which LaNi is probably the most promising (see... 

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