Abstract
In this study, multilayered AlTiN/ZrN and AlTiN/CrN/ZrN coatings with CrN layer addition were prepared by cathodic arc evaporation (CAE) system using AlTi target, Cr target and Zr targets. According to the XRD and TEM experimental results, the coatings are all B1 NaCl structure, and the columnar structure continues from the bottom CrN to the top multilayered coating and the growth of the columns is not interrupted. After CrN addition, the AlTiN/CrN/ZrN coating consisted of ZrN, AlTiN and CrN multilayers. By increasing the cathode current of Cr, thicker CrN layers were obtained. The nanoindentation results showed that the AlTiZrN had the highest hardness of 30.4 GPa and residual stress of -3.1 GPa, mainly due to the contribution of ZrN into AlTiN. The multilayered Al12Ti7Cr12Zr22N and Al8Ti5Cr21Zr17N coatings with different CrN layer thicknesses had lower hardness values. Compared to the low hardness of CrN (~18 GPa), the multilayered AlTiN/CrN/ZrN coating still possessed high hardness enough. In addition, after CrN addition, the multilayered Al12Ti7Cr12Zr22N and Al8Ti5Cr21Zr17N coatings had lower residual stresses (-1.6-2.6 GPa). The low residual stress of the hard coating is beneficial for tribological applications. For the ball-on-disc tribological tests, although the AlTiN/ZrN coating had the highest hardness but it had the highest wear rate (4.96 x 10(-6) mm(3)/Nm). The multilayered Al12Ti7Cr12Zr22N coatings with thin CrN layer addition and small Cr content had the best wear performance with the lowest wear rate of 4.21 x 10(-7) mm(3)/Nm. The results showed that the special multilayered AlTiN/CrN/ZrN hard coating possessed better wear performance than that of AlTiN/ZrN coating, which was due to the fact that the multilayer architecture with CrN addition effectively released the internal stress to resist abrasion wear.
NSTL
Elsevier