Improvement of Surface Properties of Carbon Steel Through Electrospark Coatings from Multicomponent Hard Alloys

This work demonstrates the possibility of creating effective composite coatings with a complex structure and phase composition on carbon steel C45 via electrospark deposition (ESD) with multicomponent electrodes with a bonding mass composition of Co-Ni-Cr-B-Si semi-self-fluxing alloys and superhard compounds WC, B4C and TiB2. The variation in the roughness, thickness, composition, structure, microhardness and wear at the friction of the coatings as a function of the ratios between the bonding mass and the high-hardness components in the composition of the electrode and of the pulse energy for ESD has been studied. It has been established that with a content of the bonding mass in the electrode of 25–35%, coatings with improved adhesion and simultaneously higher hardness and toughness are obtained. Suitable electrode compositions and optimal pulse energy have been defined, which provide dense and uniform coatings with an increased amount of crystalline-amorphous structures, as well as intermetallic and wear-resistant phases, with thickness, roughness and microhardness that can be changed by the ESD modes in the ranges of δ = 8–65 µm, Ra = 1.5–7 µm, and HV 8.5–15.0 GPa, respectively, and minimal wear of the coated surfaces that is up to 5 times lower than that of the substrate and up to 1.5 times lower than that obtained with conventional WC-Co electrodes.