We report on cyclic voltammetry and in situ electrochemical atomic force microscopy (EC-AFM) studies of localized corrosion of duplex 2205 stainless steel (DSS 2205) and austenitic stainless steel of the type AISI 316L in two model solutions, including artificial saliva (AS) and a simulated physiological solution known as - Hankćs solution (PS). The AFM topography analysis illustrated the higher corrosion resistance of DSS 2205 steel for the chosen range of electrochemical potentials that were applied to the steel surface in both solutions. In contrast, pitting corrosion was observed at the surface of AISI 316L steel, with the pits becoming more evident, larger and deeper, when the sample was electrochemically treated in the PS. On both surfaces the growth of corrosion products formed during the oxidation process was observed. As a result, depending on the samplećs metallurgical structure, different types of oxides covered the surface close to the breakdown potential. We distinguished between the square-like type of oxides on the surface of the DSS 2205, and the AISI 316L with its ellipse-like oxide deposits. The X-ray photoelectron spectroscopy (XPS) revealed the chemical composition of the deposition products, which consisted of two main elements, Fe and Cr. However, the oxides of the alloying elements Ni and Mo were negligible compared to the bulk.
F.02 Acquisition of new scientific knowledge
COBISS.SI-ID: 4723738The microstructure of a commercially available Ni-Ti shape-memory alloy was investigated with Scanning Electron Microscopy (SEM), Energy-Dispersive X-ray Spectroscopy (EDS) and Electron Backscatter Diffraction (EBSD) patterns. The material investigated was a Ni-Ti shape-memory alloy with the chemical composition in the mass fraction: C 0.1 %, Ni 45 % and Ti 54.9 %. The microstructure of the alloy consisted of nanosized crystal grains of the Ni-Ti phase and particles of titanium carbides. The majority of the particles were aligned in the longitudinal direction parallel to the wire's axis. The problems occurring during the EBSD analysis of the Ni-Ti phase are discussed and some orientational relationships between the carbides and the matrix are suggested.
F.02 Acquisition of new scientific knowledge
COBISS.SI-ID: 850346