Zn-Composition-Dependent Microstructure and Type I Hot Corrosion of (CuMnNiCoZnx)O High-Entropy Oxides

Abstract

This study investigates the effect of high-entropy oxide (HEO) powders (Cu, Mn, Ni, Co, Zn-x/ x = 0, 0.1, 0.2, 0.3 ) on performance under aggressive Type I hot corrosion conditions. HEO powders synthesized by the co-precipitation method were sub-jected to hot corrosion tests at 800 degrees C for 24 h under a 70% Na2SO4+30% V2O5 salt mixture, representing the aggressive conditions caused by the use of low-quality fuel in aviation. The findings suggest that increasing Zn content is associated with a reduction in the stability of the initially dominant spinel phase, accompanied by a greater tendency for the formation of low-melting point vanadate phases. In particu-lar, the presence of the Co3V2O3 phase, which exhibits a ladder-like structural motif, appears to be related to changes in the HEO crystal structure and may contribute to the development of thicker, lamellar, and irregular corrosion products on the sur-face. Consequently, Zn addition appears to be associated with enhanced growth of corrosion products, possibly through its influence on diffusion-related processes and structural stability.