Structural Сharacteristics, Mechanical Properties, Wear and Oxidation Resistance of Coatings in the Mo–Y–Zr–Si–B System Obtained on Molybdenum by Magnetron Sputtering in the DCMS and HIPIMS Modes

Abstract—Mo–(Y, Zr)–Si–B coatings were obtained by direct current magnetron sputtering (DCMS) and high-power impulse magnetron sputtering (HIPIMS) using composite targets of MoSi₂ + 10% MoB and (MoSi₂ + 10% MoB) + 20% ZrB₂, with the Y segments located in their erosion zone with a total area of 5 and 10 cm². The structure and composition of the coatings were studied by scanning and transmission electron microscopy, glow discharge optical emission spectroscopy, and XRD. The hardness, elastic modulus, elastic recovery, adhesive strength, and resistance of the coatings to abrasive wear and cyclic impact loading were determined. The oxidation resistance and thermal stability were estimated by heating the coatings to a maximum temperature of 1000°C in a muffle furnace and in a transmission electron microscope column, respectively. It has been established that the Mo–Si–B coating contains the h-MoSi₂ phase with preferred orientation in the [110] direction and crystallite size of 75 nm. Alloying of Zr and Y coatings, as well as the transition from DCMS to HIPIMS mode, contributed to the suppression of preferential growth of crystallites, increasing their dispersity and the volume fraction of the amorphous phase, which led to an increase in the crack resistance and adhesive strength of the coatings. The HIPIMS method in coating deposition caused an increase in the hardness and elastic modulus by 10%; resistance to cyclical impact, by 60%; and abrasive resistance, by 20%; it also increased oxidation resistance up to 20%. Mo–Y–Zr–Si–B coatings with the optimal composition demonstrated high thermal stability; the main structural component is the hexagonal phase h-MoSi₂; it remained in the temperature range of 20–1000°C and also resulted in a more than ninefold increased oxidation resistance of the Mo substrate at 1000°C.