Effectiveness of Ni–NiO–B4C Coatings Produced by Detonation Spraying for the Cutting Tools of Centrifugal Sugar Beet Cutters

In centrifugal sugar beet cutters, the cutter is the key component, and its efficiency has a considerable influence on the productivity and the quality of the sugar obtained. Laminar coatings may considerably improve its productivity. Such coatings may be designed so as to increase tool life and increase the cutting efficiency. In addition, their hardness and self-sharpening help prevent wear of the cutting edge. A coating of nickel-clad boron carbide powder is applied to experimental samples of 40G steel, by detonation spraying. That simulates the cutting edge of unribbed blades of 1011-V type. The coating has a dense uniform laminar structure, without cracks or pores containing boron carbide (B4C) powder. The B4C particles measure less than 10 µm and are uniformly distributed in the Ni–NiO metal–ceramic matrix. The mean hardness of the coating is 770 HV, which is more than triple the substrate hardness. These results show that hardening of the tool surface is effective and provide valuable information for improving coatings by enhancing self-sharpening in the course of operation.