Multi-response optimization of mechanical properties for ZrWN films grown using grey Taguchi approach

Abstract

ZrWN nitride films are prepared using direct current (dc) reactive magnetron sputtering. Grey Taguchi analysis is used to determine the effect of deposition parameters (substrate plasma etching time, N2/(N2+Ar) flow rates, deposition time, and substrate temperature) on the microstructure and the tribological properties. An orthogonal array, signal-to-noise ratio and analysis of variance are used to determine the effects of deposition parameters. The substrates are pretreated using oxygen plasma etching. The resulting ZrWN coatings are homogeneous, very compact and completely adhered to the substrate. In the confirmation runs, using grey Taguchi analysis, the coefficient of friction decreases from 0.45 ± 0.02 to 0.35 ± 0.02, the corrosion potential increases from − 0.201 ± 0.01 to − 0.072 ± 0.01 V, the Vickers hardness increases from 23.63 ± 0.07 to 24.65 ± 0.05 GPa, and reduced modulus increases from 115.82 ± 1.13 to 136.17 ± 1.18 GPa. The ZrWN films are characterized using X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), Rockwell C indentation and scratch testing. The TEM pattern for the ZrWN films corresponds to the (111), (200) and (220) planes of the face center cubic structure. Samples with a ZrWN film coating are classified as HF1 and exhibit good adhesive strength. The signal of friction and the associated acoustic emission signal are analyzed, and the scratch profile is analyzed using an optical microscope. Results show that the adhesive force for the critical load Lc2 is about 76.2 ± 0.5 N.