Effects of zirconium on the surface structures of the fluorinated hydrogen-absorbing alloys

The aim of this work was to utilize the F-treatment method to obtain a Ni-rich surface which has catalytic effects on the electrochemical characteristics of hydrogen-absorbing alloys. During the F-treatment of the hydrogen-absorbing alloys (AB(5)-type alloys), e.g. in the case of LaNi5, the Ni was partially dissolved into the F-solution, during the formation of LaF3 on the surface. By analysing the treatment results for different kinds of alloys, it was found that different ions have different dissolving speeds. By utilizing this property, if some appropriate elements (e.g. zirconium) are selected to be added to the LaNi5 alloys, the surface composition might be changed through F-treatment.