Erosion–corrosion at elevated temperature represents a critical degradation mechanism in components exposed to particle-laden gaseous flows, such as industrial boilers and combustion systems. This study evaluates the combined erosion–corrosion behaviour of atmospheric plasma-sprayed (APS) coatings based on Al2O3/TiO2 (97/3, 87/13, and 50/50 wt.%), TiO2, and a hybrid Al2O3/NiCrAlY (90/10 wt.%) system. Coatings were characterised by scanning electron microscopy, X-ray diffraction, Vickers microhardness and porosity analysis, and subsequently tested under solid particle erosion and cyclic oxidation at 200 and 400 °C with impact angles of 30° and 90°. All coatings exhibited significantly higher hardness (446–597 HV) than the AISI 310 substrate (181 HV), together with distinct differences in porosity and interlamellar cohesion. Erosion rates decreased with increasing temperature for both impact angles; however, the synergistic contribution to total degradation increased, particularly under normal impact (90°). This behaviour indicates that thermochemical activation enhances the nonlinear interaction between mechanical damage and oxidation. Coatings with lower defect connectivity showed reduced synergistic effects, demonstrating that microstructural architecture governs the magnitude of combined degradation. The Al2O3/NiCrAlY system exhibited improved thermomechanical stability associated with the formation of protective Al- and Cr-rich oxides.
Aperador et al. (Fri,) studied this question.