Depletion effects at phase boundaries in 2205 duplex stainless steel characterized with SKPFM and TEM/EDS

2205 duplex stainless steel, which had undergone two different heat treatments, was characterized by means of SEM/EDS, TEM/EDS, magnetic force microscopy (MFM) and scanning Kelvin probe force microscopy (SKPFM). In general, paramagnetic austenite was found to exhibit the highest Volta potential, followed by non-magnetic sigma phase and ferromagnetic ferrite. The local Volta potential drop at the phase boundaries is clearly visible in the slowly cooled sample with sigma phase precipitate while it is not notable in the solution-annealed reference sample. Chemical composition line analyses with TEM/EDS showed the depletion of Cr and Mo at the phase boundaries.