Corrosion resistance of AlN and Fe3Al reinforced Fe-based plasma cladding layer in 3.5 wt% NaCl solution

Abstract

Fe-based cladding layers were prepared via the plasma cladding method using nitrogen as protective and reactant gas. The effects of Al on the phase structure, morphology, composition, and corrosion resistance of the cladding layers were investigated. The based cladding layer consisted of α-Fe, Cr, and small amounts of CrN and FexN, whereas Fe3Al, Cr5Al8 and AlN occurred in the cladding layer with Al. Many AlN particles less than 4 μm in diameter were uniformly distributed in the cladding layer. The nitrides in the cladding layer could accelerate the formation of a passive film and increase the corrosion resistance of the cladding layer. A compact and stable passive film composed of Al2O3, Cr2O3, α-FeOOH, and Fe3O4 formed on the surface of the cladding layer with Al, which is beneficial in protecting the substrate and significantly improving the cladding layer's corrosion resistance.