Intergranular corrosion of a Fe-Cr alloy surface enriched in Mo or Ni by electron beam alloying

A superficial layer, enriched in Mo (2 to 8 at. %) and Ni (12 wt %) onto a FeCr alloy substrate, has been obtained using the electron beam alloying technique. The crystallographic structure of the melted layer is identified by SEM and TEM. The potentiodynamic current-voltage curves are recorded and the intergranular corrosion resistance is evaluated after potentiostatic attack in the transpassive range in 0.5 M H2SO4. The influence of the matrix impurities as C, P, Ti, and S must be taken into account, In fact, some elements may segregate in the grain-boundaries of the new alloy and in some cases induce a harmful intergranular corrosion.