Influence of the atomization gas on the microstructure and magnetic properties of spray-formed Fe–3%Si–3.5%Al alloys

Despite, the homogeneous and refined microstructure, spray-formed deposits of binary Fe–Si alloys with high silicon content are still difficult to hot/cold roll due to A2-disordered/B2-ordered reactions. The addition of aluminum to Fe–Si alloys may be able to keep the A2-disordered phase metastable at temperatures below 973 K, allowing the deposits to be rolled without cracking while adequately maintaining their magnetic properties. This study is a first attempt to investigate the microstructure and the magnetic properties of spray-formed Fe–3 wt.%Si–3.5 wt.%Al alloy. Argon and nitrogen were used as atomization gases. The addition of aluminum to Fe–Si alloys led to the successful production of thin sheets (0.5 mm thickness) from spray-formed deposits when using argon as atomizing gas. In contrast, the use of nitrogen led to the formation of AlN particles, resulting in excessive brittleness of the spray-formed deposit, which fractured during cooling to room temperature. Otherwise, the magnetic properties of the Fe–3.0 wt.%Si–3.5 wt.%Al alloy performed very well when compared with binary Fe–6.5 wt.%Si, especially when spray formed with argon.