Study on the Penetration of Al into Fe-3 %Si Thin Sheet Using PVD Method and Its Application in Preparing Fe-6.5 %(Si+Al) Alloy

Fe-6.5 %Si alloy has excellent soft magnetic properties but is hardly able to being produced by conventional hot-cold rolling processes.It is well known that a small amount of Al adding into Fe-Si alloys is benefit to enhancing the alloy's soft magnetic properties and its working performance.In the present work pure Al layers were deposited onto Fe-3 %Si thin sheets using direct current (DC) magnetron sputtering and followed by diffusion annealing to promote Al penetrating into low-Si steel substrates.Based on the experimental and simulation results, the mechanism of Al penetrated into low-Si steel substrate was subjected to rate-controlling and Si uphill diffusion only occurred under the influence of penetrated Al being gradient distributed.As deposited Al layer's thickness reached to 32 μm onto 0.23 mm Fe-3 %Si substrate and followed by a diffusion annealing at 1200 °C for 6 h, Fe-6.5 %(Si+Al) alloy can be achieved.Electron dispersive spectroscopy (EDS) analyses showed that both Si and penetrated Al profiles were evenly distributed along the depth of the prepared Fe-6.5 %(Si+Al) alloy, and the microstructure was also uniform and density.The resistivity of Fe-6.5 % (Si+Al) alloy was close to that of Fe-6.5 %Si alloy, but the working performance of the former was observed evidently better than the latter.