Cutting performance of nanocomposite Cr–C–N, Cr–Si–N and Cr–Si–C–N coated tools for micro end-milling operation

CrN-based multi-component coatings were deposited by a hybrid coating system combining arc ion plating (AIP) and a sputtering technique. In this paper, comparative studies on mechanical properties and cutting performance among Cr–C–N, Cr–Si–N and Cr–Si–C–N coatings were systematically conducted. Adding carbon and silicon atoms into CrN coatings had large effects on microstructural change and mechanical properties of CrN coatings by instrumental analyses such as XRD and HRTEM. The hardness value of Cr–Si–C–N coatings showed about 45 GPa, while those of Cr–Si–N and Cr–C–N coatings were 34 and 23 GPa, respectively. Cutting tests were carried out to evaluate the characteristics of micro cutting in a vertical machining center using an ultra-high-speed air turbine spindle. Consequently, the quaternary Cr–Si–C–N coated micro end-mill in dry machining showed good cutting performance under ultra-high-speed cutting conditions.