Influence of AlN layers on mechanical properties and thermal stability of Cr-based nitride coatings

► CrN/AlN, CrAlN/AlN, CrAlYN/AlN multilayer coatings ► Cr-based nitride layers (100 nm) and either 3 nm or 10 nm thin AlN layers ► Cubic AlN for 3 nm thin layers and wurtzite structure for 10 nm thin layers ► Increased hardness for the multilayer coatings composed of 10 nm thin AlN layers ► Hardness increases to 36 GPa for CrAlYN/AlN coatings due to annealing at 900 °C.