Microstructural and magnetic properties study of Fe–P rolled sheet alloys

• We have studied magnetic properties and microstructure of Fe1−xPx rolled sheet alloys.
• Increasing phosphorous content increases the B50 from 1.65 to 1.70 T.
• Increasing phosphorous content causes the decline of the eddy current loss.
• The grain size increases about 3 times with increasing phosphorous concentration.
• The hysteresis loss decreases with increasing the phosphorous content (88%).

In the work presented here, the soft magnetic properties of Fe1−xPx (x=0.36, 0.7, 1.1 at%) rolled sheet alloys were investigated. In this respect, the as-rolled sheets were subjected to a two steps annealing processes; the first one between 800 and 1000 °C for 1 h referred as first stage annealing and the second one at lower temperatures (500 and 600 °C) for 30 min, referred as second step annealing. BH tracer measurements at 50 Hz showed that for all of the phosphorous containing alloys, in general, the magnitude of coercivity decreased by applying these two annealing steps compared to those of as-rolled samples. For all of the studied samples, the B50 values measured at 50 Hz were in the range of 1.6–1.7 tesla (T). Samples having highest amount of phosphorous (1.1 at%) exhibited lower eddy current loss compared to the rest of the specimens due to the increased electrical resistivity. Besides, microstructural studies revealed that the prepared samples were free from Fe3P phase precipitation and the average grain size increased (~three times) with increasing the phosphorous content giving rise to the decrease of hysteresis losses. Further, amongst the whole prepared samples, the alloy containing 1.1 at% P showed the lowest hysteresis loss (6.99 W/kg), eddy current loss (9.25 W/kg) as well as the highest magnetic induction (1.7 T) at 5000 A/M (B50).