Structure and properties of nanostructured ceramic matrix composite coatings prepared in-situ by reactive plasma spraying micro-sized Al–Fe2O3–Cr2O3 powders

Nanostructured FeAl2O4-based ceramic matrix composite coatings were prepared in-situ by reactive plasma spraying micro-sized Al–Fe2O3 and Al–Fe2O3–Cr2O3 powders. The microstructure, toughness, Vickers hardness, and adhesive strength of these coatings were investigated by X-ray diffraction, scanning electron microscopy, transmission electron microscopy and mechanical tests. The results indicated that both the coatings exhibited a nanostructured microstructure. The grains of coating AFC sprayed with Al–Fe2O3–Cr2O3 powders are finer than those of the coating AF sprayed with Al–Fe2O3 powders. The composite nano-coating sprayed with Al–Fe2O3–Cr2O3 powders exhibited higher hardness and better wear resistance compared with those of the composite nano-coating sprayed with Al–Fe2O3 powders. The adhesive strength, toughness, and wear resistance of the composite coating sprayed with Al–Fe2O3–Cr2O3 powders were significantly enhanced compared with those of the composite coating sprayed with Al–Fe2O3 powders, which were attributed to the Cr2O3 addition.