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Abstract

Metallic glasses of the type (Fe,Co) 75Si15B10 were obtained by rapid solidification using melt spinning technique. Such materials are magnetically soft and their possible use in transformer cores can reduce hysteresis losses by 70%. This study evaluates both the magnetic properties and corrosion resistance of magnetically soft metallic glasses in relation of cobalt content and cristallinity. This work proved that the progressive replacement of iron by cobalt significantly improves corrosion resistance in chloride environments: The electrochemical impedance spectroscopy results indicated that the Co75Si15B10 alloy showed a low frequency impedance five orders of magnitude greater than the sample Fe75Si15B10. The weight loss results corroborate this finding. On the other hand, samples with co

balt exhibit an magnetically softer behavior evidencing that the coercive field decreases with increasing the cobalt content and that the hysteresis loss can be reduced by 30%. On the other hand, shows a lower value of magnetization and saturation flux over Fe75Si15B10 sample, which can be a disadvantage in the case of transportation of large magnetic fluxes. Amorphous samples exhibit a better performance with regard to corrosion resistance than crystalline and semi-crystalline counterparts, proving the hypothesis that the presence of nanoprecipitados generated more

electrochemical active regions in the precipitate-matrixinterfacesof corrosion / erosionwith respect to the surrounding matrix.