Mechanisms of coercivity

It generally is accepted that the mechanism of coercivity in the Alnicos is incoherent rotation of single-domain particles of the a -phase based on shape anisotropy. As coercivity increases, the larger the aspect ratio of the tods and the smoother thek surface becomes the difference between the saturation polarizations of the two phases also increases. It is thought that Ti increases the coercivity of Alnico because of an increased aspect ratio of the rods and a smoother surface. 

---