New highly magnetic and oxidation-resistant FeCo-based alloys

A new type of amorphous and nanocrystalline alloys has recently been produced and called HITPERM. These alloys are FeCo-based and their soft magnetic properties persist to α–γ phase transformation at 980 °C. Their soft magnetic properties are attributed to α′-FeCo phase formation during the crystallization process. The FeCo-based alloys (HITPERM) present superior magnetic flux density and permeability when compared to Fe-based alloys (FINEMET and NANOPERM). Because these alloys are potentially applicable in components working at high temperatures, their oxidation behavior and magnetic properties require careful analysis. This work present a magnetic property and oxidation resistance comparison of one traditional FeCo-based alloy and one traditional Fe-based alloy: Fe38.5Co38.5Nb7Cu1B15 (HITPERM) and Fe73Nb3Si13.5B9.5Cu1 (FINEMET); other with Si addition: Fe36Co36Nb6Cu1Si10B11; other with Cu suppression: Fe36Co36Nb7Si10B11 and a new one composition with highly magnetic and oxidation resistance: Fe33.5Co33.5Nb7Si15B11.