Microstructure and mechanical properties of atomic layer deposited alumina doped zirconia

摘要

Atomic layer deposited alumina doped zirconia films can exhibit advanced mechanical properties with potential to increase the suitability of ZrO 2 films for mechanically resilient coatings. In the present study, Al 2 O 3 -doped ZrO 2 films were deposited on a TiN substrate to thicknesses around 100?nm at 300?°C. A zirconia film containing 4.6 mol.?% Al 2 O 3 was crystallized in its tetragonal polymorph. Increasing the Al 2 O 3 content up to 5.8 and 8.2 mol.?% stabilized the cubic polymorph in the ZrO 2 -based films. The films with even higher Al 2 O 3 contents remained amorphous. All the crystalline films possessed a preferential grain orientation to extents differing beneath the surface and in the vicinity of the substrate. The most rigid films with hardness up to 15?GPa and elastic modulus above 170?GPa could be obtained when crystallized in the form of cubic ZrO 2 stabilized upon doping with Al 2 O 3 . For all the crystalline films, the hardness and elastic modulus increased near the substrate.