This study deposited CrAlN coatings from Al₅₀Cr₅₀ targets using high-power impulse magnetron sputtering, with a focus on the effects of nitrogen content and substrate bias voltage on the deposition rate, microstructure, crystal orientation, residual stress, and mechanical properties of the coating. The nitrogen content was adjusted by varying the N₂/Ar flow ratio between 20% and 140%. Increasing the nitrogen flow rate during deposition led to corresponding decreases in the deposition rate and film thickness. X-ray diffractometer (XRD) analysis revealed that a low N₂/Ar flow ratio (40%) resulted in an face-centered cubic (FCC) phase. Bias voltage also had considerable influence on the residual stress and grain size. A refined grain structure and high internal stress resulted in hard CrAlN coatings. Among the various parameter combinations evaluated in this study, the highest hardness (35.4 GPa) and highest elastic modulus (426 GPa) were obtained using an N₂/Ar flow ratio of 100% and a bias voltage of −120 V.

We investigated the effects of substrate rotation speed on the structural and mechanical properties of CrN/CrAlSiN multilayer coatings produced using high-power impulse magnetron sputtering (HiPIMS) on silicon and high-speed steel (HSS) substrates. Structural analysis and characterization of the multilayer coatings were performed using an X-ray diffractometer (XRD), field emission scanning electron microscopy (FE-SEM), an electron probe microanalyzer (EPMA), and a transmission electron microscope (TEM). The thickness of the bi-layer film depended on the substrate rotation speed, as follows: 12 (1.5 rpm), 9.5 (2 rpm), 6 (3 rpm), 4 (4 rpm), and 3.2 nm (5 rpm). The results revealed that the hardness and coating–substrate adhesion strength increased inversely with the thickness of the bi-layer. TEM analysis revealed smaller columnar structures in thinner CrN/CrAlSiN multilayer coatings. The highest results for hardness (20.1 GPa), elastic modulus (336 GPa), and adhesion strength (77 N) were obtained at a substrate rotation speed of 5 rpm. We also investigated the adhesion properties of the multilayer structures and formulated a hypothesis to explain adhesion strength.

Zr-Cu based thin-film metallic glass (TFMG) has good glass-forming ability and the addition of a third element can create a chaotic system capable of inhibiting the nucleation and growth of crystals. This study focused on TFMGs made with Zr, Cu, and Ti in various compositions deposited via high-impulse magnetron sputtering on silicon and 304 stainless-steel substrates. Detailed analysis was performed on the microstructure and surface characteristics of the resulting coatings. Transmission electron microscopy revealed that the multilayer structure changed to a nanocrystalline structure similar to an amorphous coating. The excellent hydrophobicity of Zr-Cu-Ti TFMGs can be attributed to their ultra-smooth surface without any grain boundaries. The excellent antimicrobial effects can be attributed to a hydrophobic surface resisting cell adhesion and the presence of copper ions, which are lethal to microbes.

In this study, five AlTiCrN nitride coatings were deposited via high-power impulse magnetron sputtering (HiPIMS). The AlTiCrN coatings were synthesized with high contents of Al or Ti and a lower fraction of Cr, using Ti and Al₇₀Cr₃₀ targets with five different input power ratios. Electron probe microanalyzer results revealed that the increased rate of Ti contents in the coatings can be divided into two regions due to the difference of power densities for HiPIMS (>0.5 kW/cm²) and modulated pulsed power (MPP) (<0.5 kW/cm²). The deposition rate and thickness of the coatings depended on the sputtering yield of two metal targets under HiPIMS and MPP modes. The grain size of the coatings decreased from 60 to 40 nm as the input power ratios of the AlCr/Ti targets decreased due to their lower thickness values and lower Al content. Selected area electron diffraction patterns and X-ray diffraction results revealed that the TiN and AlTiN phases can be found in the coating containing higher Ti content, whereas the AlN, CrN, and AlCrN phases were observed in the coating with a higher Al concentration. Nevertheless, decreasing the concentration of Ti had a detrimental effect on the mechanical properties of AlTiCrN coatings, due to a promotion in grain size and the formation of AlN, which is softer than TiN. It is noticed that our results differed from those in previous reports, in which a grain refinement effect was observed due to increasing Al content. In this work, the effect of processing the parameters of the HiPIMS and MPP power systems on the grain size and the mechanical property of the coating was also discussed.