Effect of Ni Content on Double-Target Co-sputtered CrNiN Coatings

Double-target co-sputtered CrNiN coatings were deposited by DC-pulsed magnetron reactive sputtering. The nickel content increases from 0.7 to 5.0 at.% with the increased Ni target current from 0.10 to 0.40 A. The influence of Ni content on preferred orientation and properties of CrNiN coatings was investigated. The results show that the doped Ni enters CrN to form (Cr,Ni)N solid solution. CrNiN coatings are mainly composed of CrN phase and demonstrate CrN(111) preferred orientation. All the coatings present columnar growth pattern. And the less obvious the preferred orientation, the more intense competitive growth, the less sufficient the columnar growth, the finer the columnar crystal and the denser the microstructure. In spite of the most dense structure with finest grains, the hardness of CrNiN coating containing 0.7 at.% Ni is the lowest. The hardness is affected by multiple effects of preferred orientation, grain size, solid solution strengthening, morphology and stress, especially the intensity degree of preferred orientation.