Synthesis and investigation of ZrC-coatings with Ni-nanodiamond electroplatings to improve the wood-cutting tool

Abstract

Different types of chemical wear (corrosion and oxidation) of hard alloys (based on tungsten carbide WC and cobalt) tools are proved to play a significant role in destruction of cutting edge blade during processing of plate wooden materials. This leads to pulling out of grain from the surface of tungsten carbide cutting element [1]. Traditionally, physical vapor deposition (PVD) was proved to be one of the most effective ways of protecting knife blade surface made of hard alloys. On other side, woodcutting tools with the application of synthetic diamond were offered [2]. Ni- and Cr-electroplatings were used in engineering to improve wear resistance of woodworking tools. The aim of this work was to synthesize and investigate (phase composition, hardness, and etc.) of thin ZrC-Ni-nanodiamond coatings on the surface of knife blades made of hard alloys. The combined ZrC-Ni-nanodiamond coatings (thickness of 1.5 µm) consist of separate phases of ZrC, α-Ni, Ni-ultradisperse diamonds phase and ultradisperse diamonds phase similar to the graphite phase. The microhardness of Ni-nanodiamond electroplatings was 5.8-6.1 GPa. The value of microhardness of Ni-nanodiamond electroplatings increased from 3.1 to 6.1 GPa with rising the concentration of nanodiamonds from 1 to 4 g/l in the electrolyte. The structure of Ni-nanodiamond coating formed by clusters of nanodiamonds influences the surface morphology of the ZrC-Ni-nanodiamond coating. The pilot tests of coated knives blades while milling laminated chipboard were carried out with the processing center ROVER B 4.35 (Italy). If compared with bare tool, the durability period of tool with ZrC-Ni-nanodiamond coated blades increased in 1.3 times.