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Chemical analysis, x-ray diffraction and magnetic force microscopy (MFM) were used to differentiate the ferromagnetic and paramagnetic phases in samples of solution annealed and aged 2205 duplex stainless steel. The samples exhibited no changes in lattice parameters and the MFM technique proved successful in clearly imaging the magnetic domain structure of the ferrite phase.

Abstract: This paper discusses the corrosion behavior of supermartensitic stainless steel in CO2-saturated synthetic seawater. A comparison is also made with an aerated solution. Potentiodynamic polarization measurements were taken in synthetic seawater with five different chloride contents: 20000, 30000, 40000, 60000 and 80000ppm, and at three different temperatures: 5, 25 and 60°C. The pitting potential decreased in a logarithmic relation with the chlorine concentration. The pitting potential decreased linearly with increasing temperature. XPS measurements indicated that the presence of CO2 enriches the Cr content in the oxide layer and that the temperature also favors this enrichment. The pitting potential depends on the stability of passive film. Otherwise, stability is dependent on the composition. So pitting potential is affected by a synergy between the chloride concentration and the saturated CO2 solution. [Copyright &y& Elsevier]

Amorphous FeMBCu (M=Nb, Zr) and FeNbSiBCu alloys with nanometer size crystallites have attracted attention due to their soft magnetic properties. The mechanism through which crystallization affects the corrosion and the comparative effect of corrosion on magnetic properties of FeMBCu (M=Nb, Zr) and FeNbSiBCu alloys has not yet been evaluated. In this paper the effect of partial crystallization on corrosion resistance of amorphous Fe73Nb3Si15.5B7.5 Cu1 and Fe80Zr3.5Nb3.5B12Cu1 alloy ribbons and the comparative effect of corrosion on saturation magnetic flux density, Bs, of these alloys were investigated. The samples were characterized by X-ray diffraction, differential scanning calorimetry and X-ray photoelectron spectroscopy. Corrosion resistance evaluation was carried out by measuring mass loss of samples immersed in 0.1 M H2SO4 solution, and by measuring potentiodynamic polarization curves (potential vs. current). Saturation magnetic flux density, Bs, of the samples were measured. After partial crystallization of Fe80Zr3.5Nb3.5B12Cu1 amorphous sample the corrosion resistance decreased, while for the Fe73Nb3Si15.5B7.5Cu1 the corrosion resistance increased. The decrease of Bs after treatment in the corrosion solution as observed in the nanocrystalline Fe80Zr3.5Nb3.5B12Cu1 sample was larger than that observed for both amorphous and the nanocrystalline Fe73Nb3Si15.5B7.5Cu1 samples after the same treatment. [Copyright &y& Elsevier]