NANOCRYSTALLIZATION BY NITRIDING TREATMENT OF FESIB-BASED AMORPHOUS RIBBONS

In FeSiB-based systems, nanocrystalline state needed for good soft mag netic properties is obtained by controlling nucleation and growth rate s of crystallization. These rates are known to depend on the additive elements in the FeSiB alloys but also on the annealing treatment. Gene rally, Cu and Nb are chosen as additive elements and conventional ther mal treatment (C.T.T.) is used to produce the nanocrystalline phase. I n this work, we studied Fe73.5Cu1Si13.5B12, Fe74Nb3Si14B9 and Fe73.5Cu 1Nb3Si13.5B9 ribbons. To obtain the nanocrystalline state, in addition to C.T.T., we used a nitriding thermochemical treatment (N.T.T.) at a pproximate to 520 degrees C and we show that this treatment improves t he nanocrystalline state (smaller grain size D and higher crystalline volume fraction). This treatment also increases the Curie temperature of the crystalline alpha-FeSi' phase.