The effect of the deposition parameters on structure and phase composition of Ti-Al-Cr-Zr-Nb-N coatings manufactured by the arc-PVD method is studied. The effect of the arc current on the elemental composition of the coatings is ascertained. Obtaining a coating with a single- or two-phase structure based on TiN or ZrN + TiN nitrides with diluted atoms of metal (Nb, Cr, or Al) is found to be feasible by means of controlling the arc current. The coatings are characterized by high values of hardness, modulus of elasticity, and adhesion/cohesion strength. The tests under conditions of a continuous cutting show that the wear resistance of a coated tool increases by a factor of 5.5.

Comparative investigations of the structural characteristics and functional properties of Ti–Al–Mo–N and Ti–Al–Mo–Ni

This work is devoted to the development of a new hybrid method of deposition of coatings based on ion-plasma arc sputtering and magnetron sputtering. The objects of investigation were samples of coatings of the Ti-Al-N system on the VK-6 hard-alloy plates obtained by three different methods, namely, ion-plasma sputtering, magnetron sputtering, and hybrid sputtering. Deposition processes were performed under the rarefaction of 1.3 × 10⁻³ Pa at a substrate temperature of 550–600°C. A VT-5 alloy of the composition Ti-Al (6 at %) was used as the sputtered material. The phase and elemental compositions of the coatings, their mechanical properties (microhardness and the Young modulus), and adhesion strength were studied. All samples were tested under the conditions of continuous cutting. The results of investigations showed that the coating obtained by the hybrid method possesses a complex of positive properties of the ion-plasma and magnetron coatings, specifically, a high adhesion strength along with the uniformity of the composition and structure, which explains its increased durability.

The influence of the compressive and tensile stresses forming in the nanostructured Ti–Al–N coatings during deposition on their physical-mechanical properties was studied. The modifying influence of metal components (Ni and Cu) introduction into Ti–Al–N coatings, which do not interact with nitrogen and have limited solubility with the nitride phase, was also under research. Coatings were deposited on WC–(6 wt.%)Co carbide cutting inserts with an arc-PVD method using a cathodic vacuum arc evaporation apparatus. The introduction of Ni and Cu to the composition leads to the reduction of nitride phases grain size in both investigated coatings from 120 to 10–12 nm for Ti–Al–Cu–N and to 15–18 nm for Ti–Al–Ni–N. Thus, the hardness increases from 29 to 43 and 51 GPa for the mentioned above coatings, respectively. Meanwhile, Ti–Al–Cu–N and Ti–Al–Ni–N coatings are characterized by tensile stresses about 0.12–0.32 MPa against the much higher value of compressive stresses in Ti–Al–N coatings (4.29–5.31 GPa). The modification of Ti–Al–N coatings also leads to the changing of their destruction mechanism during the scratch-test. The critical loads characterizing the emergence of the first cracks in the coatings and complete abrasion of the coating (L_c1 and L_c3) were determined. They had the value of 20; 22 N (L_c1) and 64; 57 N (L_c3) for Ti–Al–Ni–N; Ti–Al–Cu–N coatings, respectively. The L_c1 parameter for Ti–Al–N coatings was much lower and was equal to 11 N. Along with those, Ti–Al–N coatings destructed according to the adhesion mechanism when the critical load was 35 N. In addition, the decreasing level of compressive stresses in Ti–Al–Cu–N and Ti–Al–Ni–N coatings as compared to that in the Ti–Al–N coating, their crack resistance during multi-cycle shock-dynamic impact test was significantly higher. The results can indicate that high hardness and crack resistance of the coatings is to a greater extent determined by coatings nanostructuring, not the stresses value. In addition, it confirms the possibility to obtain coatings with low stresses value while maintaining their superhardness.