Composite coatings for cutting tools after ion mixing

Abstract

Ways of increasing the wear resistance of "duplex" coatings applied to cutting tools due to preliminary diffusion saturation of the tool surface with nitrogen followed by physical deposition of a hard coating (Ti, Cr)N are proposed. The proposed coating, in addition to the above, contains an additional modified layer with an impurity of ions (metals: Ti, Zr, W and Al in combination with three non-metals N, C, and O), applied to a prenitrided surface of high-speed steel before the deposition of a hard coating. The highest wear resistance after "triplex"-treatment was achieved by ion implantation of titanium into a prenitrided surface. The coefficient of friction of the modified layer is studied at different contact temperatures. An improved ability of a layer with an ionic mixture to accumulate elastic deformation energy is shown. Ionic mixing contributes to the appearance of a thin surface layer with an amorphous-like structure, which prolongs the stage of normal wear, significantly increasing the tool life as a result of the self-organization process.