Effect of Multilayer Cr/CrN Coatings Deposited by Magnetron Sputtering on the Thermal Stability and High-Temperature Steam Oxidation Resistance of Zirconium Alloy E110

The effect of the multilayer structure of Cr/CrN coatings deposited by reactive magnetron sputtering on zirconium alloy E110 (Zr–1Nb) on their thermal stability and resistance to steam oxidation at 1100 °C was studied. Coatings with different numbers of alternating Cr and CrN sublayers (1, 2, 4, and 6) were fabricated using experimental methods of X-ray diffraction (XRD) and scanning electron microscopy with energy-dispersive analysis (SEM/EDS). It was shown that an increase in the number of alternating Cr and CrN sublayers leads to the preservation of the cubic phase of CrN, the formation of a dense structure, and a decrease in Cr–Zr interdiffusion. After testing, multilayer coatings retaining the internal structure and a sufficiently structurally dense Cr2O3 layer effectively ensured air penetration. The best thermal stability was demonstrated by a six-layer coating, ensuring minimal oxidation and preservation of the E110 substrate.