Abstract
TiSiN nanocomposite coatings with different thickness were deposited on D2 tool steel substrates using unbalance magnetron sputtering (UBMS). The purpose of this study was to investigate the influence of coating thickness on the compositions, structure, mechanical properties, and corrosion resistance of TiSiN coatings. The effect of Ti interlayer on structure and properties of TiSiN coatings was also studied. The coating thickness increased with increasing deposition duration ranging from 696 to 3019 nm and the maximum thickness could reach over 3 μm. TiN (111) was the preferred orientation in all TiSiN coatings. The incorporation of Si or addition of Ti interlayer could change the preferred orientation of TiN phase from (200) to (111) in TiSiN coatings. The results of X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS) revealed that the nanocomposite coatings were composed of nanocrystalline TiN and amorphous SiNx. The hardness, ranging from 23 to 36 GPa, was related to the grain size and texture of TiN in TiSiN coatings. The residual stresses of TiN in nanocomposite coatings measured by XRD cos2αsin2ψ method were all compressive and had no significant variation with increasing coating thickness. The results of the potentiodynamic polarization scan indicated that the TiSiN-coated samples possessed good corrosion resistance in both 0.5 M H2SO4 and 5 wt% NaCl solutions. From the results of scratch test and potentiodynamic polarization scan, the addition of Ti interlayer was beneficial for the adhesion strength and corrosion resistance of the TiSiN coatings.