Investigation of the tribological and operational properties of (Me_x,Mo_y, Al_1-(x+y)N (Me -Ti, Zr or Cr) coatings

The paper discusses the properties of the (Me-x,Mo-y,Al1-(x+y))N coatings, where Me means titanium, zirconium, or chromium. The studies were focused on the phase and elemental compositions of the coatings, and their hardness and adhesive bond strength to the substrate were found. The investigation of the tribological properties found that while at temperature of 400 degrees C, the lowest value of the adhesion component ha of the coefficient of friction (COF) was registered for the Ti-TiN-(Ti,Mo,Al)N and Cr-CrN-(Cr,Mo,Al)N coatings, then at temperatures of 550 degrees C and higher, the lowest value of f(adh) was observed for the Zr-ZrN-(Zr,Mo,Al)N coating. The study of cutting properties during the turning of steel discovered the best wear resistance of a tool with the Zr-ZrN-(Zr,Mo,Al)N coating. Special attention was paid to the diffusion and oxidation processes in the area of the "coating-material being machined" interface. In the mentioned area, the zones of plastic deformation of the coating, formed under the cutting conditions, were discovered and investigated. The studies reveal that plastic deformation deteriorates the barrier properties of the coating layers with respect to the diffusion of iron. The Zr-ZrN-(Zr,Mo,Al)N coating has a balanced combination of high hardness and relatively low value of f(adh, )due to which it resists well to abrasive and adhesive-fatigue wear.