Abstract: A metal powder having a composition including the following elements, expressed in content by weight: 6.5%?Si?10%, 4.5%?Nb?10%, 0.2%?B?2.0%, 0.2%?Cu?2.0%, C?2% and optionally containing Ni?10 wt % and/or Co?10 wt % and/or Cr?7 wt % and/or Zr as a substitute for any part of Nb on a one-to-one basis and/or Mo as a substitute for any part of Nb on a one-to-one basis and/or P as a substitute for any part of Si on a one-to-one basis, the balance being Fe and unavoidable impurities resulting from the elaboration, the metal powder having a microstructure including at least 5% in area fraction of an amorphous phase, the balance being made of crystalline ferritic phases with a grain size below 20 ?m and possible precipitates, the metal powder having a mean sphericity SPHT of at least 0.80.