Comparative study of CrAlSiN monolayer and CrN/AlSiN superlattice multilayer coatings: Behavior at high temperature in steam atmosphere

Protective coatings that retard ionic diffusion at high temperature in the presence of steam are of interest for the energy industry. A CrAlSiN monolayer and two CrN/AlSiN coatings of periodic layers of different thicknesses deposited on P92 steel by cathodic arc evaporation (CAE) were studied. Their protection capabilities under the working conditions of ultrasupercritical steam turbines (at 650 °C in 100% steam atmosphere) up to 2000 h were assessed. Several characterization techniques were used to achieve this objective, such as gravimetric analysis, X-ray diffraction (XRD), scanning electron microscopy with an energy dispersive detector (SEM-EDS), field emission scanning electron microscopy (FE-SEM) and glow discharge optical emission spectrometry (GDOES).