LAUSR

Abstract The inhomogeneity of the Curie temperature in large-sized LaFe13−x−yCoxSiyC0.15 alloys is studied. The Curie temperature of the large-sized LaFe13−x−yCoxSiyC0.15 alloys shows a decreasing tendency from the edge to the sub-edge region of the alloy, while the Curie temperature of the small-sized sheet-shaped LaFe11.2Co0.5Si1.3C0.15 alloy is same in different regions. Besides, chemical analysis shows that the Co and Si content reveals a decreasing tendency from the edge to the sub-edge region in large-sized alloys as well, which may be attributed to the segregation of Co and Si element during slow solidification in large-sized LaFe13−x−yCoxSiyC0.15 alloys. So it can be inferred that the segregation of Co and Si could result in the inhomogeneity of Curie temperature in large-sized LaFe13−x−yCoxSiyC0.15 alloys. Moreover, both the experiment and the calculation find that the mixed usage of the inhomogeneous LaFe13−x−yCoxSiyC0.15 alloys will reduce the maximum magnetic entropy change, which needs more attention in industrial application of La(Fe1−xSix)13 based alloys.