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Corrosion behavior of Fe-based ferromagnetic (Fe, Ni)–B–Si–Nb bulk glassy alloys in aqueous electrolytes

“…The corrosion behavior of the present glassy alloys is similar to that of pure Ni or Fe, implying that the main constituent elements Fe and Ni could be responsible for their polarization behavior owing to the fact that the alloy Nb content is insufficient so that these glassy alloys could not undergo passivation spontaneously. An apparent active to passive transition has also been found for Fe 40 Ni 40 P 14 B 6 amorphous and Fe 43.2 Co 28.8 B 19.2 Si 4.8 Nb 4 glassy alloys in the same electrolyte [20,27]. It can be seen from Fig.…”

Corrosion Behaviour of [(Fe<SUB>0.6</SUB>Co<SUB>0.4</SUB>)<SUB>0.75</SUB>B<SUB>0.2</SUB>Si<SUB>0.05</SUB>]<SUB>96</SUB>Nb<SUB>4</SUB> Bulk Glassy Alloy in Sulphuric Acid Solutions

“…This may be attributed to the structural relaxation and stress relief caused by annealing. 25) It is known that during structural relaxation the metallic glass tends to a more stable structure, thereby causing a decrease in the reactivity of its elements and increasing the alloy's chemical stability. The lower mass loss and corrosion current density of the sample annealed at 773 K, compared to the sample annealed at 573 K, mean that the higher temperature annealing results in greater structural relaxation, thereby increasing the corrosion resistance.…”

Effect of irreversible structural relaxation on the electrochemical behavior of Fe78−xSi13B9Cr(x=3,4,7) amorphous alloys

“…This atomic mobility might explain the increase in DG Ã by a decrease of the residual stresses during densification at lower temperature. It has been reported that the observed beneficial effect of relaxation in the corrosion resistance of amorphous alloys [16] may be associated with the redistribution of the chemical elements on the surface and a decrease of the residual stresses.…”

“…Few studies on structural relaxation in amorphous alloys prepared by the melt-spinning method have been reported including corrosion resistance effects [11][12][13][14][15][16][17]. It was reported [12] that melt-spun amorphous Ni-19P alloys in different amorphous states showed significantly different potentiodynamic polarization curves.…”

“…The effect of structural relaxation on the corrosion behavior of cobalt-based (Co 69 Fe 5 MoSi 15 B 10 ) and iron-nickel-based (Fe 40 Ni 40 P 14 B 6 ) amorphous alloys [16] is beneficial to their corrosion resistance. A low temperature annealing leads to the formation of a denser amorphous structure which may result in a decrease of the anodic activity and/or an enhancement of the susceptibility to passivation.…”