High entropic coatings FeCrNiTiZrAl and their properties

Abstract

In our proposed empirical model, the anisotropy of the surface energy and the thickness of the surface layer of the high-entropy FeCrNiTiZrAl alloy are calculated. The thickness of the surface layer of this alloy is about 2 nm, which is an order of magnitude greater than the thickness of the surface layer of complex crystals, but is of the same order of magnitude as that of metallic glasses. The hardness and other properties of the high-entropy alloy are the same as for metallic glasses, but are 2-3 times higher than the hardness of stainless steels. The surface energy of the high-entropy FeCrNiTiZrAl alloy is about 2 J/m2, which corresponds to the surface energy of magnesium oxide and other crystals with a high melting point. However, unlike these crystals, the friction coefficients of a high-entropy alloy (~ 0.06) are much lower than that of ordinary steels (~0.8). We have theoretically shown that the friction coefficient is proportionally dependent on the surface energy and inversely proportional to the Gibbs energy, which significantly decreases for a high-entropy alloy, leading to low friction. The high hardness and low coefficient of friction of the high-entropy alloy facilitates the deposition of coatings from them on structural metal products, which contributes to their widespread use.