Interrelation structure-composition electrochemical alloy properties FINEMET modified with beryllium.

The main aim of this work is to study the influence of the compositional changes made in the FINEMET (Fe73.5Si13.5B9Cu1Nb3) type alloys and its interrelationship with the electrochemical behaviour. Beryllium has been chosen as an alloying element for its contribution of greater hardness, better mechanical properties, greater thermal and electrical conductivity and a more passive character to these alloys. Copper and niobium have been replaced by beryllium in order to study its effect on the clusterization and the refining of grain during the nano-cristalization process. The variations on the electrochemical behaviour, will be related to the structural changes obtained as a result of the controlled crystallization process, as well as to the replacement of the different alloying elements. In the electrochemical study, cyclic voltametry techniques have been used in KOH 0.5 M solution, potentiodinamic polarization in NaCl 0.1 M solution and corrosion test en KCl 1.5 M + KOH 0.5 M solution. The structural characterization and the cristallization kinetic study have been done by X-Ray diffraction and differential scanning calorimetry. As the experimental results have show, we can conclude that thanks to the introduction of Beryllium, an improvement on the FINEMET alloy's electrochemical behaviour has been achieved, whether amorphous ("as-quenched state") or whether in thermally treated state.