Mechanical properties of LaNi5 thin films prepared by sputtering and vapor deposition methods and determination of the hydrogen content in these films

Amorphous LaNi5 films were prepared using a sputtering method. Mechanical properties and hydrogenation characteristics of the films were investigated and the results were compared with those of the deposited films. The density of the sputtered LaNi5 film was about 6 g/cm3, which was larger than that of the evaporation deposited film but smaller than that of crystalline LaNi5. Thermal conductivities of amorphous films were larger than those of bulk samples. Mechanical strength of the sputtered films deposited on various substrates was measured after 100 cycles of hyrogen absorption--desorption process. The result was in the following order for the substrates used: Ni foil>Ni>Al foil>Cu foil>Cu>Al>glass. The hydrogen content in a sputtered film with a thickness of 1.3 μm was found to be 2.4 H/LaNi5. The hydrogen concentration in the film increased monotonically with increasing the hydrogen pressure in both cases between 333 and 363 K