Industrial-scale sputter deposition of Cr1−xAlxN coatings with 0.21 ≤ x ≤ 0.74 from segmented targets

This study introduces novel triangle-like segmented targets for industrial-scale sputtering systems, which enable to distinctly reduce the workload in economic coating material development. Al, Cr and Cr/Al 50/50 target segments were assembled pairwise to synthesize Cr1−xAlxN hard coatings in the range of 0.21 ≤ x ≤ 0.74 at a high compositional resolution within two deposition runs. The obtained coating compositions are supported with TRIM simulations showing distinct differences in the sputtering characteristics of Al and Cr. X-ray diffraction reveals a solubility limit of x = 0.61 in cubic Cr1−xAlxN. The evolution of structural and mechanical properties with composition is discussed in detail. The high potential and industrial relevance of the coatings with a maximum hardness of 25.2 GPa is corroborated by excellent tribological properties with low friction values down to 0.4 and wear coefficients down to 1.8·10−16 m3/Nm.