Morphology and microstructure of Mg-Ti-H films deposited by microwave plasma-assisted co-sputtering

Abstract Mg-Ti-H films with a Ti content in the range 0 ≤ at.% Ti  2 phase and have a dense microstructure with discontinuous columnar grains. For the films with a medium Ti content (2.7 ≤ at.% Ti ≤ 6.6), the β–MgH 2 , metastable orthorhombic γ–MgH 2 and Mg-Ti phases were found in different proportions, with a typical columnar growth. The abrupt microstructural changes of the films with a Ti content >10 at.% correlate with the change in crystallinity. These films exhibit a mainly amorphous/nanocrystalline structure with a granular morphology. We showed that the Ti content plays a significant role in the formation of structural and microstructural features of the Mg-Ti-H films, which might be a useful parameter in tuning the functional properties of magnesium hydride.