Electrospark Deposition of Fenicrbsic–Meb2 Coatings on Steel

Abstract

The effect of TiB2 and CrB2 additions to the commercial self-fluxing FeNiCrBSiC eutectic alloy on the structurization of electrospark coatings was examined. The mass transfer kinetics in the electrospark deposition of FTB20 (FeNiCrBSiC + 20% TiB2) and FCB20 (FeNiCrBSiC + 20% CrB2) composite materials and commercial self-fluxing FeNiCrBSiC alloy coatings onto steel 45 using an Alier-52 unit was studied. When the energy parameters of electrospark deposition increased, the mass transfer coefficient became higher and the electrospark coatings thicker and rougher. To reinforce the steel surfaces of machine parts operating in sliding friction conditions, application of the FTB20 and FCB20 coatings using an Alier-52 unit (2 and 4 modes at 1– 2 min/cm2) is recommended. The electrospark deposition of FTB20 and FCB20 electrodes leads to a heterophase structure on steel, consisting of an iron–nickel matrix and fine inclusions of chromium and/or titanium borides. The boride sizes in the developed coatings reach about 1 μm, which is one order of magnitude smaller than in the electrode materials (20 μm). In the deposition of the FCB20 electrode on steel, numerous cracks generate in the modified layer and deteriorate the service properties. The addition of TiB2 and CrB2 to the self-fluxing alloy increases the wear resistance of the electrospark coatings by four to five times as compared to the coatings produced from the commercial self-fluxing FeNiCrBSiB alloy (PG-Zh14 grade).