Dependence of the properties of multicomponent FeNiCrCoAlTiCuMoVZrNbW high-entropy coating on 35 steel on the parameters of electrospark deposition

Abstract

High-entropy alloys form a new class of metallic materials attracting the interest of researchers by a broad range of attractive properties and applications. The multicomponent FeNiCrCoAlTiCuMoVZrNbW coatings were obtained on 35 steel as a result of electric spark treatment in granules of the corresponding metals. We studied the structure and compositions of the coatings by X‑ray phase diffraction analysis and scanning electron microscopy supplemented by the energy-dispersive analysis. The thermodynamic calculations revealed high-entropy structures of the deposited coatings with BCC and FCC lattices confirmed by the results of phase diffraction analysis. As the duration of discharge pulses of electric spark deposition increases from 20 to 200 μsec, the thickness of the coating increases from 4.7 to 25.8 μm. The water wetting angles of the surfaces of applied high-entropy coatings vary from 102.4 to 106.6°, which means that the surface of 35 steel acquires hydrophobic properties. The heat resistance of the coated samples at a temperature of 700 °C was 3.7–4.9 times higher than for 35 steel. It was discovered that high-entropy coatings may significantly decrease the corrosion potential and corrosion current density of 35 steel in a 3.5% NaCl solution. The microhardness of the coatings varied within the range 5.11–5.31 GPa. As the duration of discharge pulses of spark deposition increases, the friction coefficient of the high-entropy coatings monotonically increases from 0.86 to 0.97. The application of multicomponent FeNiCrCoAITiCuMoVZrNbW high-entropy coatings enables us to attain a 2–4-fold lowering of the degree of wear of 35 steel.