STRUCTURE AND PROPERTIES OF Cr–DND/ Hf–Zr–ZrN COATINGS ONWOODCUTTING TOOLS

Abstract

In this work research of the structure and properties features of combined Cr – detonation nanodiamonds (DND)/ Hf–Zr–ZrN coatings synthesized on steel (grade 6HC) chopping knives of wood-cutting tools by ion-beam sputtering and Arc-PVD vacuum methods as well as galvanic treatment have been conducted. The microstructure of the coatings by SEM, EDX techniques have been studied. Moreover, methods of a microidentation and pilot testing of coatings have been used. The coatings Cr–DND/ Hf–Zr–ZrN have a layered structure. There is an intermediate ZrN layer between Cr–DND top and ZrHf bottom layers which are not mixed with each other. The maximum value of the microhardness of the Hf–Zr–ZrN coating is 6.6±0.3 GPa. Held pilot tests of Cr–DND/ Hf–Zr–ZrN coated cutting tools have proved their increasing durability period to be 1.7––1.9 times higher, if compared with bare tools, when cutting blanks from pine and deciduous wood.