Structure and properties of nanostructured Fe(AlCr)2O4–Cr–(AlCr)2O3–Fe composite coating prepared by plasma spraying

In-situ nanostructured Fe(AlCr)2O4-based composite coating (FACr52.5 coating) was prepared by reactive plasma spraying with micro-sized Al–Fe2O3–Cr2O3 powders. The microstructure, toughness and Vickers hardness, and adhesive strength of the coating were investigated by X-ray diffraction, scanning electron microscopy, transmission electron microscopy and mechanical tests. The results indicated that the interlamellar spacing of the FACr52.5 coating is only 1 μm. The coating exhibited nanostructured microstructure. The in-situ Cr (20 nm) and Fe (50–200 nm) particles were uniformly distributed in an Fe(AlCr)2O4 matrix, while the grain size of the Fe(AlCr)2O4 matrix is about 60 nm. The FACr52.5 composite nano-coating exhibited much higher hardness, better wear resistance, stronger adhesive strength and toughness as compared to those of the composite nano-coating sprayed with Fe2O3–Al powders. Excellent mechanical properties of the FACr52.5 coating were attributed to the uniform distribution of the in-situ nano-sized Cr particles in the coating matrix.