CHARACTERIZATION OF RF MAGNETRON-SPUTTERED CrCuN AND CrNiN COATINGS BY NANOINDENTATION

Abstract

RF magnetron-sputtered CrCuN coatings with ultra-low Cu content (0.53–2.1 at.%) were deposited using Cr[Formula: see text]Cu3 target (at.%) by changing the substrate negative bias from 0[Formula: see text]V to [Formula: see text]200[Formula: see text]V. The CrNiN coatings with different nickel contents (0, 2.92 and 8.79 at.%) were sputtered by different-component Cr–Ni alloy targets (Cr, Cr[Formula: see text]Ni5 and Cr[Formula: see text]Ni[Formula: see text], in at.%). The effect of bias and alloying element content on coating toughness was investigated by nanoindentation. The results show that all the coatings have unsatisfied toughness because of [Formula: see text]/[Formula: see text]. With increasing bias, the toughness of CrN and CrCuN coatings improves basically due to grain refinement caused by high bias effect. Under the same bias, although CrCuN coatings have finer grains, their toughness is still lower than that of CrN coatings because of inadequate copper coverage degree as a result of ultra-low copper content. On the contrary, once there is an appropriate alloying element content of 2.92 at.% Ni, the toughness of CrNiN coatings increases with the nickel content due to relatively higher Ni coverage degree.