N coated tools are commonly used in high-speed machining, where the cutting edge of an end-mill or insert is exposed to temperatures up to 1100 °C. Here, we investigate the effect of Yttrium addition on the thermal stability
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N coated tools are commonly used in high-speed machining, where the cutting edge of an end-mill or insert is exposed to temperatures up to 1100 °C. Here, we investigate the effect of Yttrium addition on the thermal stability of Ti1-x
N coatings. Reactive DC magnetron sputtering of powder metallurgically prepared Ti0.50
, and Ti0.46
targets result in the formation of single-phase cubic (c) Ti0.45
N, binary cubic/wurtzite c/w-Ti0.41
N and singe-phase w-Ti0.38
N coatings. Using pulsed DC reactive magnetron sputtering for the Ti0.49
target allows preparing single-phase c-Ti0.46
N coatings. By employing thermal analyses in combination with X-ray diffraction and transmission electron microscopy investigations of as deposited and annealed (in He atmosphere) samples, we revealed that Y effectively retards the decomposition of the Ti1-x-y
N solid-solution to higher temperatures and promotes the precipitation of c-TiN, c-YN, and w-AlN. Due to their different microstructure and morphology already in the as deposited state, the hardness of the coatings decreases from ~35 to 22 GPa with increasing Y-content and increasing wurtzite phase fraction. Highest peak hardness of ~38 GPa is obtained for the Y-free c-Ti0.45
N coating after annealing at Ta
= 950 °C, due to spinodal decomposition. After annealing above 1000 °C the highest hardness is obtained for the 2 mol % YN containing c-Ti0.46
N coating with ~29 and 28 GPa for Ta
= 1150 and 1200 °C, respectively.