Structure and properties of nanostructured ceramic matrix composite coatings prepared in-situ by reactive plasma spraying micro-sized Al-Fe_2O_3-Cr_2O_3 powders

摘要

Nanostructured FeAl_2O_4-based ceramic matrix composite coatings were prepared in-situ by reactive plasma spraying micro-sized Al-Fe_2O_3 and Al-Fe_2O_3-Cr_2O_3 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-Fe_2O_3-Cr_2O_3 powders are finer than those of the coating AF sprayed with Al-Fe_2O_3 powders. The composite nano-coating sprayed with Al-Fe_2O_3-Cr_2O_3 powders exhibited higher hardness and better wear resistance compared with those of the composite nano-coating sprayed with Al-Fe_2O_3 powders. The adhesive strength, toughness, and wear resistance of the composite coating sprayed with Al-Fe_2O_3-Cr_2O_3 powders were significantly enhanced compared with those of the composite coating sprayed with Al-Fe_2O_3 powders, which were attributed to the Cr_2O_3 addition.