Hot corrosion of a novel NiO/NiFe2O4 composite coating thermally converted from the electroplated Ni–Fe alloy

A novel NiO/NiFe2O4 composite coating thermally converted from an electroplated Ni–Fe alloy was successfully fabricated. The composite coating consisted of a NiO matrix and homogeneously distributed criss-cross intragranular and intergranular NiFe2O4 precipitates, with a very dense and flat structure. The composite, compared to bare Ni metal, exhibited increased hot corrosion resistance under an atmosphere of Na3AlF6–AlF3–CaF molten salts and air at 960 °C, mainly because of the dense structure and well-adhered, homogeneously dispersed intragranular and intergranular NiFe2O4 precipitates.

► A dense NiO/NiFe2O4 composite coating was successfully fabricated.
► The composite coating has a flat structure and a high (100) orientation.
► The composite coating produces a protective oxide scale with good adhesion.
► The composite coating exhibited good adhesion to the substrate in corrosion tests.