High temperature characteristics and phase compositions of Cu/Mn multilayers with the different average thickness prepared by electrodeposition

Abstract Four different Cu/Mn multilayers are prepared on ferritic stainless steel 430 by direct current deposition, and the electrodeposition behavior of Cu and Mn is studied by chronopotentiometry and cyclic voltammetry. After oxidation at 750 ℃ for 500 h, the discontinuous Si oxides are formed in the vicinity of substrate/Cr2O3 oxide interface, Cu diffuses outward faster than Mn in CuMn compound oxides, and oxide compositions of designed samples are discussed based on the Cu-Mn-O phase diagram. The Cu-Mn compound oxide coatings do not effectively block outward diffusion of Fe, but effectively block Cr. The ASR value of the sample with the ratio of Cu/Mn about 1 is the lowest among all the samples, though its thickness of oxide layer (~15 μm) is in the middle of all samples. Besides Cr2O3 and SiO2, the formation of Mn3O4 and Fe2O3 oxides with low conductivity lead to the high ASR.