Efficiency of Application of (Mo, Al)N-Based Coatings with Inclusion of Ti, Zr or Cr during the Turning of Steel of Nickel-Based Alloy

Abstract

The article compares the properties of multilayer composite wear-resistant coatings of Zr–ZrN–(Zr, Mo, Al)N, Ti–TiN–(Ti, Mo, Al)N, and Cr–CrN–(Cr, Mo, Al)N. The investigation was focused on hardness, resistance to fracture during scratch tests, elemental composition, and structure of the coatings. Experiments were carried out to study the wear resistance of coated carbide tools during the turning of 1045 steel and of NiCr20TiAl heat-resistant nickel alloy. With the elemental compositions identical in the content of molybdenum (Mo) and aluminium (Al), identical thicknesses and nanolayer periods of λ, the coatings being studied demonstrated a noticeable difference in wear resistance. Both during the turning of steel and nickel-based alloy, the highest wear resistance was detected for tools with the Zr–ZrN–(Zr, Mo, Al)N coating (the tool life was 3–5 times higher than for uncoated tools). The good wear resistance of the Zr–ZrN–(Zr, Mo, Al)N coating may be related to the optimal combination of hardness and plasticity and the active formation of molybdenum oxide (MoO3) on the coating surface during the cutting, with good tribological and protective properties.