Hard ZrO2/Al2O3 nanolaminated PVD coatings evaluated by nanoindentation

Abstract ZrO 2 /Al 2 O 3 coatings have been deposited by DC reactive magnetron sputtering with a nanolayered structure thickness of 3/3.5, 6/7 and 12/14 nm of each layer. The aim of this work is to study the mechanical properties of the ZrO 2 /Al 2 O 3 nanolaminated coatings, relate it to with the nanolayered structure, the microstructural and structural properties. The mechanical behaviour of ZrO 2 /Al 2 O 3 nanolaminated coatings was studied by nanoindentation. Low load tests were performed to study the hardness and Young's modulus after deposition and after heat treatment at 1000 °C. Tests were also performed at higher loads in order to observe the plastic behaviour of the coatings. The adhesion was also studied using scratch test measurements. In the as-deposited condition the hardness has no significant changes. However, after heat treatment it increases for all coatings and reaches 24 GPa for a ZrO 2 /Al 2 O 3 nanolaminated coatings prepared with 12/14 nm thickness of each layer.