Influence of Al addition on structure and magnetic properties of nanocrystalline Fe65Co15Si5Nb3Cu1B11-xAlx alloys

The microstructure and soft magnetic properties of amorphous and nanocrystalline Fe65Co15Si5Nb3Cu1B11-xAlx (x = 0,1, 2,3) alloys were investigated. Microstructure has been analyzed from XRD patterns and magnetic properties were mainly studied by the evolution of initial permeability (1.4) from room temperature to 700 degrees C. It was found that adding a certain amount of Al in Fe65Co15Si5Nb3Cu1B11 alloy significantly decreases onset primary crystallization temperature T-x1 from 452 degrees C to 388 degrees C and increases the crystallized interval temperature Delta T-x from 188 degrees C to 290 degrees C. However, with the Al adding, the Curie temperature of amorphous phase T-c(am) shows a decline tendency. After annealing at 550 degrees C, the alloy with x = 1 exhibited the maximum room-temperature mu(i), however, the most stable soft magnetic properties at elevated temperatures was found in the alloy with x = 3. Therefore, the (mu(i)-T) curves of Fe65Co15Si5Nb3Cu1B8Al3 samples annealed at 520-580 degrees C were also investigated in detail. (C) 2016 Elsevier B.V. All rights reserved.