BORON-CONTAINING COATINGS FORMED ON A HIGH-ENTROPY ALLOY: STRUCTURE, PROPERTIES

10.25712/ASTU.1811-1416.2023.04.005

Abstract

The aim of this work is to analyze the results obtained in the study of the structure, elemental and phase composition, strength and tribological properties of boron-containing coatings obtained on a high-entropy alloy by a complex ion-plasma method. The substrate material was a CoFeCrMnNi alloy of non-equiatomic composition (25.2 Co, 15.1 Cr, 37.8 Fe, 3.4 Mn, 16.3 Ni; at. %). Boron-containing coatings of the Al–Mg–Ti–B elemental composition with a thickness of 1, 3, and 5 μm were formed by the high-frequency ion-plasma sputtering method (magnetron high-frequency deposition under conditions of ion-plasma assistance using a «PINK» gas (argon) plasma generator). A target 200 mm in diameter, made from a mixture of two AlMgB₁₄ + 50 % TiB₂ powders, was used to carry out the deposition of a boron-containing coating. A volume argon plasma was created in the working vacuum chamber of the setup with the help of gas plasma generator «PINK» to intensify the target sputtering process. Argon ions were extracted from the plasma when an RF potential was applied to the target and bombarded the target, producing its intense sputtering. The formation of a coating on the substrate surface occurs as a result of applying a bias voltage of 35 V to it. The temperature of the substrate during coating deposition is (350-360) °C. Coating deposition rate 0.05 µm/min. Studies of the structure and elemental composition of a boron-containing coating of the Al–Mg–Ti–B elemental composition formed on samples of a high-entropy CoFeCrMnNi alloy by a complex ion-plasma method were carried out by electron diffraction microscopy. It is established that the coating has an amorphous-crystalline structure. The size of the areas of the crystalline state of the material (3-5) nm. Coating hardness H = 11.0 GPa; Young's modulus E = 185 GPa; ratio H/E = 0.059, wear parameter k = 4×10^-7mm³/N×m; friction coefficient μ = 0.12. For an uncoated substrate, H = 2.1 GPa; k = 2.9×10^-4 mm³/N×m; μ = 0.62.