A different pattern appeared concerning iron with oxides; the work of Sakai et al., 2000 and Belyakov et al., 2001-03 studied samples with oxygen 0.2% to 0.6% wt. deliberately incorporated into NC powder during mechanical milling.
Un comportamiento diferente parece tener el hierro con óxidos. Sakai et al. 2000 y Belyakov et al. 2001, 2002, 2003 estudiaron polvo NC con oxígeno deliberadamente introducido en la molienda mecánica, en porcentajes del 0,2 al 0,6% en masa.