Improvement of the performance properties of cutting tools using the multilayer composite wear-resistant coatings based on nitrides of Cr, Mo, Zr, Nb, and Al

Abstract

The article deals with the properties of the Cr,Mo-(Cr,Mo)N-(Cr,Mo,Al)N, Zr,Nb-(Zr,Nb)N-(Zr,Nb,Al)N, and Zr,Nb-(Zr,Nb)N-(Cr,Mo,Zr,Nb,Al)N multilayer composite wear-resistant coatings. The coatings were deposited using technology of Filtered Cathodic Vacuum Arc Deposition (FCVAD). The investigation of the coating structures, conducted using the transmission electron microscopy (TEM), showed the presence of the nanolayer structure with the nanolayer thicknesses within a range of 0.5–20 nm and the period λ within a range of 92–136 nm. The microhardness of the Zr,Nb-(Zr,Nb)N-(Cr,Mo,Zr,Nb,Al)N coating turned out to be significantly higher than the microhardness of the other studied coatings, and that may be associated with the formation of a multicomponent fcc phase of (Cr,Mo,Zr,Nb,Al)N. According to the results of the cutting tests during the turning of American Iron and Steel Institute (AISI) 420 steel, the tool with the Zr,Nb-(Zr,Nb)N-(Cr,Mo,Zr,Nb,Al)N coating demonstrated the tool life which 2.5 times exceeds the tool life of the tool with the (Ti,Al)N commercial coating of similar thickness and by 50 and 30% exceeds the tool life of tools with two other studied coatings. The investigation of the fracture processes in coatings during the turning revealed a significant difference in the mechanisms of cracking and wear.