Magnetic properties and microstructure of radially oriented Sm(Co,Fe,Cu,Zr) z ring magnets

Abstract: Radially oriented Sm(Co,Fe,Cu,Zr) z ring magnets are prepared by powder metallurgy with appropriate magnetic field molding, sintering process and aging treatment. The results indicate that radially oriented Sm(Co,Fe,Cu,Zr) z ring magnets have obvious anisotropy of thermal expansion and sintering shrinkage, which easily lead to the splits and deformation of the ring magnets. So, slow heating, vacuum pre-sintering in sintering process and various quenching processes at different steps during quenching are adopted. The magnets have excellent magnetic properties: B r =10.8 kGs, Hcj =27.6 kOe, BHmax =28.1 MGOe. Besides, there is a uniform magnetization field on the surface of the ring magnets. The average surface magnetization field () is 1.502 kGs. The deviation from average (α) is only 4.2%. The microstructure of the magnets consists of a mixture of homogeneous cellular and lamella structures. [Copyright &y& Elsevier]