Some unique properties of nanocrystalline metal alloys

Abstract

The remarkable modification in physical, magnetic and other consequent properties of certain ternary alloys using two representative alloy systems eg. (Ni-Cu-Al) and (Ni-Fe-Ti) nanoparticles in different concentration ranges by correlating changes in their properties with grain size, alloying composition have been studied. A sharp decrease in ferromagnetism maintaining the higher crystalline (eg. cubic) symmetry with grain size and alloying has been observed. Both of these alloys show phase transitions, whose transition temperatures are lowered as compared to similar “bulk” compositions. Such phenomenon is attributed to reduction of effective number of spins per grain upon nanostructure formation and associated change in type of crystalline phase. Representative work on maintaining such observed nano related properties in the bulk regime as a proof of concept method is also stated. These alloys in powder form have also shown a high degree of EM radiation absorption in the GHz range, possibly as a consequence of their observed magnetic properties.