Hydrogen absorption and corrosion resistance of LaNi4.8Al0.2 and LaNi4.8Al0.1Li0.1 alloys

The hydrogen absorption properties and the electrochemical corrosion characteristics of LaNi4.8Al0.2 and LaNi4.8Al0.1Li0.1 alloys were investigated in this study. The structure of the alloys was tested by X-ray diffraction (XRD) method. The ability of alloys to absorb hydrogen was characterized from the pressure-composition (P-C) isotherms at temperatures ranging from 293 to 353 K. The P-C isotherms allowed to determine thermodynamic parameters for the hydrogen desorption process. It was found that the alloys were solid solutions of CaCu5 type structure. Partial substitution of Al with Li in the alloy led to increase of the amount of absorbed hydrogen and the related plateau pressures. On the basis of potentiokinetic polarisation characteristics, it was demonstrated that the presence of Li in the alloy was advantageous from corrosion resistance point of view.